diff --git a/Orm/Xtensive.Orm/Orm/Providers/StorageDriver.Operations.cs b/Orm/Xtensive.Orm/Orm/Providers/StorageDriver.Operations.cs
index d3eaf5b036..bdeb6ce3e5 100644
--- a/Orm/Xtensive.Orm/Orm/Providers/StorageDriver.Operations.cs
+++ b/Orm/Xtensive.Orm/Orm/Providers/StorageDriver.Operations.cs
@@ -397,14 +397,14 @@ public async ValueTask ReleaseSavepointAsync(
     #region Sync Execute methods
 
     public int ExecuteNonQuery(Session session, DbCommand command) =>
-      ExecuteCommand(session, command, CommandBehavior.Default, (c, cb) => c.ExecuteNonQuery());
+      ExecuteCommand(session, command, CommandBehavior.Default, static (c, cb) => c.ExecuteNonQuery());
 
     public object ExecuteScalar(Session session, DbCommand command) =>
-      ExecuteCommand(session, command, CommandBehavior.Default, (c, cb) => c.ExecuteScalar());
+      ExecuteCommand(session, command, CommandBehavior.Default, static (c, cb) => c.ExecuteScalar());
 
     public DbDataReader ExecuteReader(Session session, DbCommand command,
       CommandBehavior behavior = CommandBehavior.Default) =>
-      ExecuteCommand(session, command, behavior, (c, cb) => c.ExecuteReader(cb));
+      ExecuteCommand(session, command, behavior, static (c, cb) => c.ExecuteReader(cb));
 
     #endregion
 
@@ -412,11 +412,11 @@ public DbDataReader ExecuteReader(Session session, DbCommand command,
 
     public Task<int> ExecuteNonQueryAsync(Session session, DbCommand command, CancellationToken cancellationToken = default) =>
       ExecuteCommandAsync(session, command, CommandBehavior.Default, cancellationToken,
-        (c, cb, ct) => c.ExecuteNonQueryAsync(ct));
+        static (c, cb, ct) => c.ExecuteNonQueryAsync(ct));
 
     public Task<object> ExecuteScalarAsync(Session session, DbCommand command, CancellationToken cancellationToken = default) =>
       ExecuteCommandAsync(session, command, CommandBehavior.Default, cancellationToken,
-        (c, cb, ct) => c.ExecuteScalarAsync(ct));
+        static (c, cb, ct) => c.ExecuteScalarAsync(ct));
 
     public Task<DbDataReader> ExecuteReaderAsync(Session session, DbCommand command,
       CancellationToken cancellationToken = default) =>
@@ -425,18 +425,27 @@ public Task<DbDataReader> ExecuteReaderAsync(Session session, DbCommand command,
     public Task<DbDataReader> ExecuteReaderAsync(
       Session session, DbCommand command, CommandBehavior behavior, CancellationToken cancellationToken = default) =>
       ExecuteCommandAsync(session, command, behavior, cancellationToken,
-        (c, cb, ct) => c.ExecuteReaderAsync(cb, ct));
+        static (c, cb, ct) => c.ExecuteReaderAsync(cb, ct));
 
     #endregion
 
-    private TResult ExecuteCommand<TResult>(
-      Session session, DbCommand command, CommandBehavior commandBehavior, Func<DbCommand, CommandBehavior, TResult> action)
+    private void PreDbCommandExecuting(Session session, DbCommand command, CancellationToken ct = default)
     {
       if (isLoggingEnabled) {
         SqlLog.Info(nameof(Strings.LogSessionXQueryY), session.ToStringSafely(), command.ToHumanReadableString());
       }
 
-      session?.Events.NotifyDbCommandExecuting(command);
+      ct.ThrowIfCancellationRequested();
+      if (session is not null) {
+        session.Transaction?.CheckForTimeout(command);
+        session.Events.NotifyDbCommandExecuting(command);
+      }
+    }
+
+    private TResult ExecuteCommand<TResult>(
+      Session session, DbCommand command, CommandBehavior commandBehavior, Func<DbCommand, CommandBehavior, TResult> action)
+    {
+      PreDbCommandExecuting(session, command);
 
       TResult result;
       try {
@@ -457,12 +466,7 @@ private async Task<TResult> ExecuteCommandAsync<TResult>(Session session,
       DbCommand command, CommandBehavior commandBehavior,
       CancellationToken cancellationToken, Func<DbCommand, CommandBehavior, CancellationToken, Task<TResult>> action)
     {
-      if (isLoggingEnabled) {
-        SqlLog.Info(nameof(Strings.LogSessionXQueryY), session.ToStringSafely(), command.ToHumanReadableString());
-      }
-
-      cancellationToken.ThrowIfCancellationRequested();
-      session?.Events.NotifyDbCommandExecuting(command);
+      PreDbCommandExecuting(session, command, cancellationToken);
 
       TResult result;
       try {
diff --git a/Orm/Xtensive.Orm/Orm/Session.Transactions.cs b/Orm/Xtensive.Orm/Orm/Session.Transactions.cs
index a68c035d04..5108b51a0f 100644
--- a/Orm/Xtensive.Orm/Orm/Session.Transactions.cs
+++ b/Orm/Xtensive.Orm/Orm/Session.Transactions.cs
@@ -21,7 +21,7 @@ public partial class Session
   {
     private const string SavepointNameFormat = "s{0}";
 
-    private readonly StateLifetimeToken sessionLifetimeToken;
+    private readonly StateLifetimeToken sessionLifetimeToken = new StateLifetimeToken();
     private readonly List<StateLifetimeToken> promotedLifetimeTokens;
     private int nextSavepoint;
 
@@ -409,10 +409,7 @@ private void EnsureIsolationLevelCompatibility(IsolationLevel current, Isolation
       throw new InvalidOperationException(Strings.ExCanNotReuseOpenedTransactionRequestedIsolationLevelIsDifferent);
     }
 
-    private string GetNextSavepointName()
-    {
-      return string.Format(SavepointNameFormat, nextSavepoint++);
-    }
+    private string GetNextSavepointName() => $"s{nextSavepoint++}";
 
     private void ClearChangeRegistry()
     {
diff --git a/Orm/Xtensive.Orm/Orm/Transaction.cs b/Orm/Xtensive.Orm/Orm/Transaction.cs
index 60490b54f7..463060e9f3 100644
--- a/Orm/Xtensive.Orm/Orm/Transaction.cs
+++ b/Orm/Xtensive.Orm/Orm/Transaction.cs
@@ -6,6 +6,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Data.Common;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
@@ -29,12 +30,7 @@ public sealed partial class Transaction : IHasExtensions
     /// Gets the current <see cref="Transaction"/> object
     /// using <see cref="Session"/>.<see cref="Orm.Session.Current"/>.
     /// </summary>
-    public static Transaction Current {
-      get {
-        var session = Session.Current;
-        return session?.Transaction;
-      }
-    }
+    public static Transaction Current => Session.Current?.Transaction;
 
     /// <summary>
     /// Gets the current <see cref="Transaction"/>, 
@@ -45,16 +41,8 @@ public static Transaction Current {
     /// <exception cref="InvalidOperationException">
     /// <see cref="Transaction.Current"/> <see cref="Transaction"/> is <see langword="null" />.
     /// </exception>
-    public static Transaction Demand()
-    {
-      var current = Current;
-      if (current == null) {
-        throw new InvalidOperationException(
-          Strings.ExActiveTransactionIsRequiredForThisOperationUseSessionOpenTransactionToOpenIt);
-      }
-
-      return current;
-    }
+    public static Transaction Demand() =>
+      Current ?? throw new InvalidOperationException(Strings.ExActiveTransactionIsRequiredForThisOperationUseSessionOpenTransactionToOpenIt);
 
     /// <summary>
     /// Checks whether a transaction exists or not in the provided session.
@@ -69,7 +57,7 @@ public static void Require(Session session)
 
     #endregion
 
-    private readonly List<StateLifetimeToken> lifetimeTokens;
+    private readonly List<StateLifetimeToken> lifetimeTokens = new(1);
 
     private ExtensionCollection extensions;
     private Transaction inner;
@@ -77,50 +65,62 @@ public static void Require(Session session)
     /// <summary>
     /// Gets a value indicating whether this instance is automatic transaction.
     /// </summary>
-    public bool IsAutomatic { get; private set; }
-    
+    public bool IsAutomatic { get; }
+
     /// <summary>
     /// Gets a value indicating whether this instance is 
     /// transaction running locally.
     /// </summary>
-    public bool IsDisconnected { get; private set; }
-    
+    public bool IsDisconnected { get; }
+
+    private Guid? guid;
     /// <summary>
     /// Gets the unique identifier of this transaction.
     /// Nested transactions have the same <see cref="Guid"/> 
     /// as their outermost.
     /// </summary>
-    public Guid Guid { get; private set; }
+    public Guid Guid => Outer?.Guid ?? (guid ??= Guid.NewGuid());
 
     /// <summary>
     /// Gets the session this transaction is bound to.
     /// </summary>
-    public Session Session { get; private set; }
+    public Session Session { get; }
 
     /// <summary>
     /// Gets the isolation level.
     /// </summary>
-    public IsolationLevel IsolationLevel { get; private set; }
+    public IsolationLevel IsolationLevel { get; }
 
     /// <summary>
     /// Gets the state of the transaction.
     /// </summary>
-    public TransactionState State { get; private set; }
+    public TransactionState State { get; private set; } = TransactionState.NotActivated;
 
     /// <summary>
     /// Gets the outer transaction.
     /// </summary>
-    public Transaction Outer { get; private set; }
+    public Transaction Outer { get; }
 
     /// <summary>
     /// Gets the outermost transaction.
     /// </summary>
-    public Transaction Outermost { get; private set; }
+    public Transaction Outermost => Outer?.Outermost ?? this;
 
     /// <summary>
     /// Gets the start time of this transaction.
     /// </summary>
-    public DateTime TimeStamp { get; private set; }
+    public DateTime TimeStamp { get; } = DateTime.UtcNow;
+
+    private TimeSpan? timeout;
+    /// <summary>
+    /// Gets or sets Transaction timeout
+    /// </summary>
+    public TimeSpan? Timeout {
+      get => timeout;
+      set => timeout = IsNested
+          ? throw new InvalidOperationException(Strings.ExNestedTransactionTimeout)
+          : value;
+    }
 
     /// <summary>
     /// Gets a value indicating whether this transaction is a nested transaction.
@@ -130,7 +130,7 @@ public static void Require(Session session)
     /// <summary>
     /// Gets <see cref="StateLifetimeToken"/> associated with this transaction.
     /// </summary>
-    public StateLifetimeToken LifetimeToken { get; private set; }
+    public StateLifetimeToken LifetimeToken { get; private set; } = new();
 
     #region IHasExtensions Members
 
@@ -139,7 +139,7 @@ public static void Require(Session session)
 
     #endregion
 
-    internal string SavepointName { get; private set; }
+    internal string SavepointName { get; }
 
     /// <summary>
     /// Indicates whether changes made in this transaction are visible "as is"
@@ -287,40 +287,34 @@ private void ClearLifetimeTokens()
       LifetimeToken = null;
     }
 
+    internal void CheckForTimeout(DbCommand command)
+    {
+      if (Timeout is not null) {
+          var remain = TimeStamp + Timeout.Value - DateTime.UtcNow;
+          command.CommandTimeout = remain.Ticks > 0
+            ? Math.Max(1, (int) remain.TotalSeconds)
+            : throw new TimeoutException(String.Format(Strings.ExTransactionTimeout, Timeout));
+      }
+    }
+
     #endregion
 
-    
-    // Constructors
 
-    internal Transaction(Session session, IsolationLevel isolationLevel, bool isAutomatic)
-      : this(session, isolationLevel, isAutomatic, null, null)
-    {
-    }
+    // Constructors
 
-    internal Transaction(Session session, IsolationLevel isolationLevel, bool isAutomatic, Transaction outer,
-      string savepointName)
+    internal Transaction(Session session, IsolationLevel isolationLevel, bool isAutomatic, Transaction outer = null,
+      string savepointName = null)
     {
-      lifetimeTokens = new List<StateLifetimeToken>();
-
-      Guid = Guid.NewGuid();
-      State = TransactionState.NotActivated;
       Session = session;
       IsolationLevel = isolationLevel;
       IsAutomatic = isAutomatic;
       IsDisconnected = session.IsDisconnected;
-      TimeStamp = DateTime.UtcNow;
-      LifetimeToken = new StateLifetimeToken();
       lifetimeTokens.Add(LifetimeToken);
 
       if (outer != null) {
         Outer = outer;
-        Guid = outer.Guid;
-        Outermost = outer.Outermost;
         SavepointName = savepointName;
       }
-      else {
-        Outermost = this;
-      }
     }
   }
-} 
+}
diff --git a/Orm/Xtensive.Orm/Strings.Designer.cs b/Orm/Xtensive.Orm/Strings.Designer.cs
index 284d869e30..980d79f662 100644
--- a/Orm/Xtensive.Orm/Strings.Designer.cs
+++ b/Orm/Xtensive.Orm/Strings.Designer.cs
@@ -3084,6 +3084,15 @@ internal static string ExNestedFieldXIsNotSupported {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Nested transaction cannot have timeout.
+        /// </summary>
+        internal static string ExNestedTransactionTimeout {
+            get {
+                return ResourceManager.GetString("ExNestedTransactionTimeout", resourceCulture);
+            }
+        }
+
         /// <summary>
         ///   Looks up a localized string similar to Comparer.Current is null..
         /// </summary>
@@ -4353,6 +4362,15 @@ internal static string ExTransactionShouldNotBeActive {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Transaction is longer than {0}.
+        /// </summary>
+        internal static string ExTransactionTimeout {
+            get {
+                return ResourceManager.GetString("ExTransactionTimeout", resourceCulture);
+            }
+        }
+
         /// <summary>
         ///   Looks up a localized string similar to Translation of DateOnly.ToString(string) with arbitrary arguments is not supported. Use DateOnly.ToString(&quot;s&quot;)..
         /// </summary>
diff --git a/Orm/Xtensive.Orm/Strings.resx b/Orm/Xtensive.Orm/Strings.resx
index 730c44a495..e8ff9c95b5 100644
--- a/Orm/Xtensive.Orm/Strings.resx
+++ b/Orm/Xtensive.Orm/Strings.resx
@@ -2603,4 +2603,10 @@ Error: {1}</value>
   <data name="ExMaxNumberOfConditionsShouldBeBetweenXAndY" xml:space="preserve">
     <value>DomainConfiguration.MaxNumberOfConditions should be between {0} and {1} (included).</value>
   </data>
+  <data name="ExNestedTransactionTimeout" xml:space="preserve">
+    <value>Nested transaction cannot have timeout</value>
+  </data>
+  <data name="ExTransactionTimeout" xml:space="preserve">
+    <value>Transaction is longer than {0}</value>
+  </data>
 </root>
\ No newline at end of file