diff --git a/google-cloud-clients/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionPool.java b/google-cloud-clients/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionPool.java
index 532778b7d3e7..d992bb15df6e 100644
--- a/google-cloud-clients/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionPool.java
+++ b/google-cloud-clients/google-cloud-spanner/src/main/java/com/google/cloud/spanner/SessionPool.java
@@ -573,7 +573,7 @@ public Timestamp getCommitTimestamp() {
     @Override
     public TransactionRunner allowNestedTransaction() {
       runner.allowNestedTransaction();
-      return runner;
+      return this;
     }
   }
 
diff --git a/google-cloud-clients/google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseClientImplTest.java b/google-cloud-clients/google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseClientImplTest.java
index c0934aeeabb5..7aba1b4ba435 100644
--- a/google-cloud-clients/google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseClientImplTest.java
+++ b/google-cloud-clients/google-cloud-spanner/src/test/java/com/google/cloud/spanner/DatabaseClientImplTest.java
@@ -27,6 +27,7 @@
 import com.google.cloud.spanner.MockSpannerServiceImpl.SimulatedExecutionTime;
 import com.google.cloud.spanner.MockSpannerServiceImpl.StatementResult;
 import com.google.cloud.spanner.TransactionRunner.TransactionCallable;
+import com.google.common.base.Stopwatch;
 import com.google.protobuf.ListValue;
 import com.google.spanner.v1.ResultSetMetadata;
 import com.google.spanner.v1.StructType;
@@ -37,6 +38,7 @@
 import io.grpc.inprocess.InProcessServerBuilder;
 import java.io.IOException;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
 import org.junit.After;
 import org.junit.AfterClass;
 import org.junit.Before;
@@ -257,4 +259,102 @@ public Long run(TransactionContext transaction) throws Exception {
       assertThat(updateCount, is(equalTo(UPDATE_COUNT)));
     }
   }
+
+  @Test
+  public void testAllowNestedTransactions() throws InterruptedException {
+    final DatabaseClientImpl client =
+        (DatabaseClientImpl)
+            spanner.getDatabaseClient(DatabaseId.of("[PROJECT]", "[INSTANCE]", "[DATABASE]"));
+    // Wait until all sessions have been created.
+    final int minSessions = spanner.getOptions().getSessionPoolOptions().getMinSessions();
+    Stopwatch watch = Stopwatch.createStarted();
+    while (watch.elapsed(TimeUnit.SECONDS) < 5
+        && client.pool.getNumberOfSessionsInPool() < minSessions) {
+      Thread.sleep(1L);
+    }
+    assertThat(client.pool.getNumberOfSessionsInPool(), is(equalTo(minSessions)));
+    Long res =
+        client
+            .readWriteTransaction()
+            .allowNestedTransaction()
+            .run(
+                new TransactionCallable<Long>() {
+                  @Override
+                  public Long run(TransactionContext transaction) throws Exception {
+                    assertThat(
+                        client.pool.getNumberOfSessionsInPool(), is(equalTo(minSessions - 1)));
+                    return transaction.executeUpdate(UPDATE_STATEMENT);
+                  }
+                });
+    assertThat(res, is(equalTo(UPDATE_COUNT)));
+    assertThat(client.pool.getNumberOfSessionsInPool(), is(equalTo(minSessions)));
+  }
+
+  @Test
+  public void testNestedTransactionsUsingTwoDatabases() throws InterruptedException {
+    final DatabaseClientImpl client1 =
+        (DatabaseClientImpl)
+            spanner.getDatabaseClient(DatabaseId.of("[PROJECT]", "[INSTANCE]", "[DATABASE1]"));
+    final DatabaseClientImpl client2 =
+        (DatabaseClientImpl)
+            spanner.getDatabaseClient(DatabaseId.of("[PROJECT]", "[INSTANCE]", "[DATABASE2]"));
+    // Wait until all sessions have been created so we can actually check the number of sessions
+    // checked out of the pools.
+    final int minSessions = spanner.getOptions().getSessionPoolOptions().getMinSessions();
+    Stopwatch watch = Stopwatch.createStarted();
+    while (watch.elapsed(TimeUnit.SECONDS) < 5
+        && (client1.pool.getNumberOfSessionsInPool() < minSessions
+            || client2.pool.getNumberOfSessionsInPool() < minSessions)) {
+      Thread.sleep(1L);
+    }
+    assertThat(client1.pool.getNumberOfSessionsInPool(), is(equalTo(minSessions)));
+    assertThat(client2.pool.getNumberOfSessionsInPool(), is(equalTo(minSessions)));
+    Long res =
+        client1
+            .readWriteTransaction()
+            .allowNestedTransaction()
+            .run(
+                new TransactionCallable<Long>() {
+                  @Override
+                  public Long run(TransactionContext transaction) throws Exception {
+                    // Client1 should have 1 session checked out.
+                    // Client2 should have 0 sessions checked out.
+                    assertThat(
+                        client1.pool.getNumberOfSessionsInPool(), is(equalTo(minSessions - 1)));
+                    assertThat(client2.pool.getNumberOfSessionsInPool(), is(equalTo(minSessions)));
+                    Long add =
+                        client2
+                            .readWriteTransaction()
+                            .run(
+                                new TransactionCallable<Long>() {
+                                  @Override
+                                  public Long run(TransactionContext transaction) throws Exception {
+                                    // Both clients should now have 1 session checked out.
+                                    assertThat(
+                                        client1.pool.getNumberOfSessionsInPool(),
+                                        is(equalTo(minSessions - 1)));
+                                    assertThat(
+                                        client2.pool.getNumberOfSessionsInPool(),
+                                        is(equalTo(minSessions - 1)));
+                                    try (ResultSet rs = transaction.executeQuery(SELECT1)) {
+                                      if (rs.next()) {
+                                        return rs.getLong(0);
+                                      }
+                                      return 0L;
+                                    }
+                                  }
+                                });
+                    try (ResultSet rs = transaction.executeQuery(SELECT1)) {
+                      if (rs.next()) {
+                        return add + rs.getLong(0);
+                      }
+                      return add + 0L;
+                    }
+                  }
+                });
+    assertThat(res, is(equalTo(2L)));
+    // All sessions should now be checked back in to the pools.
+    assertThat(client1.pool.getNumberOfSessionsInPool(), is(equalTo(minSessions)));
+    assertThat(client2.pool.getNumberOfSessionsInPool(), is(equalTo(minSessions)));
+  }
 }