diff --git a/core/src/main/java/com/scalar/db/storage/dynamo/DynamoAdmin.java b/core/src/main/java/com/scalar/db/storage/dynamo/DynamoAdmin.java
index 9cd1d1b87..252900f18 100644
--- a/core/src/main/java/com/scalar/db/storage/dynamo/DynamoAdmin.java
+++ b/core/src/main/java/com/scalar/db/storage/dynamo/DynamoAdmin.java
@@ -1142,7 +1142,7 @@ public boolean namespaceExists(String nonPrefixedNamespace) throws ExecutionExce
         List<String> tableNames = listTablesResponse.tableNames();
         Namespace namespace = Namespace.of(namespacePrefix, nonPrefixedNamespace);
         for (String tableName : tableNames) {
-          if (tableName.startsWith(namespace.prefixed())) {
+          if (tableName.startsWith(namespace.prefixed() + ".")) {
             namespaceExists = true;
             break;
           }
diff --git a/core/src/test/java/com/scalar/db/storage/dynamo/DynamoAdminTestBase.java b/core/src/test/java/com/scalar/db/storage/dynamo/DynamoAdminTestBase.java
index 858e83259..c2fd99711 100644
--- a/core/src/test/java/com/scalar/db/storage/dynamo/DynamoAdminTestBase.java
+++ b/core/src/test/java/com/scalar/db/storage/dynamo/DynamoAdminTestBase.java
@@ -198,6 +198,23 @@ public void getTableMetadata_ShouldReturnCorrectTableMetadata() throws Execution
     assertThat(actualRequest.consistentRead()).isTrue();
   }
 
+  // https://github.com/scalar-labs/scalardb/issues/784
+  @Test
+  public void namespaceExists_ShouldPerformExactMatch() throws ExecutionException {
+    // Arrange
+    ListTablesResponse listTablesResponse = mock(ListTablesResponse.class);
+    when(client.listTables(any(ListTablesRequest.class))).thenReturn(listTablesResponse);
+    when(listTablesResponse.lastEvaluatedTableName()).thenReturn(null);
+    when(listTablesResponse.tableNames())
+        .thenReturn(ImmutableList.<String>builder().add(getFullTableName()).build());
+
+    // Act
+    // Assert
+    assertThat(admin.namespaceExists(NAMESPACE)).isTrue();
+    // compare with namespace prefix
+    assertThat(admin.namespaceExists(NAMESPACE.substring(0, NAMESPACE.length() - 1))).isFalse();
+  }
+
   @Test
   public void dropNamespace_ShouldDropAllTablesInNamespace() throws ExecutionException {
     // Arrange