diff --git a/ydb/core/tx/schemeshard/ut_external_data_source/ut_external_data_source.cpp b/ydb/core/tx/schemeshard/ut_external_data_source/ut_external_data_source.cpp
index c4c6d3dad58c..eb49133ff542 100644
--- a/ydb/core/tx/schemeshard/ut_external_data_source/ut_external_data_source.cpp
+++ b/ydb/core/tx/schemeshard/ut_external_data_source/ut_external_data_source.cpp
@@ -403,4 +403,80 @@ Y_UNIT_TEST_SUITE(TExternalDataSourceTest) {
 
         TestLs(runtime, "/MyRoot/ExternalDataSource", false, NLs::PathNotExist);
     }
+
+    Y_UNIT_TEST(CreateExternalDataSourceWithOrReplace) {
+        TTestBasicRuntime runtime;
+        TTestEnv env(runtime, TTestEnvOptions().EnableReplaceIfExists(true));
+        ui64 txId = 100;
+
+        TestCreateExternalDataSource(runtime, ++txId, "/MyRoot",R"(
+                Name: "MyExternalDataSource"
+                SourceType: "ObjectStorage"
+                Location: "https://s3.cloud.net/my_bucket"
+                Auth {
+                    None {
+                    }
+                }
+                ReplaceIfExists: true
+            )",{NKikimrScheme::StatusAccepted});
+
+        env.TestWaitNotification(runtime, txId);
+
+        {
+            auto describeResult =  DescribePath(runtime, "/MyRoot/MyExternalDataSource");
+            TestDescribeResult(describeResult, {NLs::PathExist});
+            UNIT_ASSERT(describeResult.GetPathDescription().HasExternalDataSourceDescription());
+            const auto& externalDataSourceDescription = describeResult.GetPathDescription().GetExternalDataSourceDescription();
+            UNIT_ASSERT_VALUES_EQUAL(externalDataSourceDescription.GetName(), "MyExternalDataSource");
+            UNIT_ASSERT_VALUES_EQUAL(externalDataSourceDescription.GetSourceType(), "ObjectStorage");
+            UNIT_ASSERT_VALUES_EQUAL(externalDataSourceDescription.GetVersion(), 1);
+            UNIT_ASSERT_VALUES_EQUAL(externalDataSourceDescription.GetLocation(), "https://s3.cloud.net/my_bucket");
+            UNIT_ASSERT_EQUAL(externalDataSourceDescription.GetAuth().identity_case(), NKikimrSchemeOp::TAuth::kNone);
+        }
+
+        TestCreateExternalDataSource(runtime, ++txId, "/MyRoot",R"(
+                Name: "MyExternalDataSource"
+                SourceType: "ObjectStorage"
+                Location: "https://s3.cloud.net/my_new_bucket"
+                Auth {
+                    None {
+                    }
+                }
+                ReplaceIfExists: true
+            )",{NKikimrScheme::StatusAccepted});
+        env.TestWaitNotification(runtime, txId);
+
+        {
+            auto describeResult =  DescribePath(runtime, "/MyRoot/MyExternalDataSource");
+            TestDescribeResult(describeResult, {NLs::PathExist});
+            UNIT_ASSERT(describeResult.GetPathDescription().HasExternalDataSourceDescription());
+            const auto& externalDataSourceDescription = describeResult.GetPathDescription().GetExternalDataSourceDescription();
+            UNIT_ASSERT_VALUES_EQUAL(externalDataSourceDescription.GetName(), "MyExternalDataSource");
+            UNIT_ASSERT_VALUES_EQUAL(externalDataSourceDescription.GetSourceType(), "ObjectStorage");
+            UNIT_ASSERT_VALUES_EQUAL(externalDataSourceDescription.GetVersion(), 2);
+            UNIT_ASSERT_VALUES_EQUAL(externalDataSourceDescription.GetLocation(), "https://s3.cloud.net/my_new_bucket");
+            UNIT_ASSERT_EQUAL(externalDataSourceDescription.GetAuth().identity_case(), NKikimrSchemeOp::TAuth::kNone);
+        }
+    }
+
+    Y_UNIT_TEST(CreateExternalDataSourceWithOrReplaceShouldFailIfFeatureFlagIsNotSet) {
+        TTestBasicRuntime runtime;
+        TTestEnv env(runtime, TTestEnvOptions().EnableReplaceIfExists(false));
+        ui64 txId = 100;
+
+        TestCreateExternalDataSource(runtime, ++txId, "/MyRoot",R"(
+                Name: "MyExternalDataSource"
+                SourceType: "ObjectStorage"
+                Location: "https://s3.cloud.net/my_bucket"
+                Auth {
+                    None {
+                    }
+                }
+                ReplaceIfExists: true
+            )",{{NKikimrScheme::StatusPreconditionFailed, "Unsupported: feature flag EnableReplaceIfExists is off"}});
+
+        env.TestWaitNotification(runtime, txId);
+
+        TestLs(runtime, "/MyRoot/MyExternalDataSource", false, NLs::PathNotExist);
+    }
 }
diff --git a/ydb/core/tx/schemeshard/ut_external_table/ut_external_table.cpp b/ydb/core/tx/schemeshard/ut_external_table/ut_external_table.cpp
index 7c8921a28139..63b4de83e840 100644
--- a/ydb/core/tx/schemeshard/ut_external_table/ut_external_table.cpp
+++ b/ydb/core/tx/schemeshard/ut_external_table/ut_external_table.cpp
@@ -312,4 +312,90 @@ Y_UNIT_TEST_SUITE(TExternalTableTest) {
                 Columns { Name: "Value" Type: "Utf8"}
             )", {{NKikimrScheme::StatusPathDoesNotExist, "Check failed: path: '/MyRoot/ExternalDataSource1'"}});
     }
+
+    Y_UNIT_TEST(CreateExternalTableWithOrReplace) {
+        TTestBasicRuntime runtime;
+        TTestEnv env(runtime, TTestEnvOptions().EnableReplaceIfExists(true));
+        ui64 txId = 100;
+
+        CreateExternalDataSource(runtime, env, ++txId);
+        TestCreateExternalTable(runtime, ++txId, "/MyRoot", R"(
+                Name: "ExternalTable"
+                SourceType: "General"
+                DataSourcePath: "/MyRoot/ExternalDataSource"
+                Location: "/"
+                Columns { Name: "key" Type: "Uint64" }
+                ReplaceIfExists: true
+            )", {NKikimrScheme::StatusAccepted});
+
+        env.TestWaitNotification(runtime, txId);
+
+        {
+            auto describeResult =  DescribePath(runtime, "/MyRoot/ExternalTable");
+            TestDescribeResult(describeResult, {NLs::PathExist});
+            UNIT_ASSERT(describeResult.GetPathDescription().HasExternalTableDescription());
+            const auto& externalTableDescription = describeResult.GetPathDescription().GetExternalTableDescription();
+            UNIT_ASSERT_VALUES_EQUAL(externalTableDescription.GetName(), "ExternalTable");
+            UNIT_ASSERT_VALUES_EQUAL(externalTableDescription.GetDataSourcePath(), "/MyRoot/ExternalDataSource");
+            UNIT_ASSERT_VALUES_EQUAL(externalTableDescription.GetLocation(), "/");
+            UNIT_ASSERT_VALUES_EQUAL(externalTableDescription.GetSourceType(), "ObjectStorage");
+            UNIT_ASSERT_VALUES_EQUAL(externalTableDescription.GetVersion(), 1);
+            auto& columns = externalTableDescription.GetColumns();
+            UNIT_ASSERT_VALUES_EQUAL(columns.size(), 1);
+            UNIT_ASSERT_VALUES_EQUAL(columns.Get(0).GetName(), "key");
+            UNIT_ASSERT_VALUES_EQUAL(columns.Get(0).GetType(), "Uint64");
+            UNIT_ASSERT_VALUES_EQUAL(columns.Get(0).GetNotNull(), false);
+        }
+
+        TestCreateExternalTable(runtime, ++txId, "/MyRoot", R"(
+                Name: "ExternalTable"
+                SourceType: "General"
+                DataSourcePath: "/MyRoot/ExternalDataSource"
+                Location: "/new_location"
+                Columns { Name: "key" Type: "Uint64" }
+                Columns { Name: "value" Type: "Uint64" }
+                ReplaceIfExists: true
+            )", {NKikimrScheme::StatusAccepted});
+        env.TestWaitNotification(runtime, txId);
+
+        {
+            auto describeResult = DescribePath(runtime, "/MyRoot/ExternalTable");
+            TestDescribeResult(describeResult, {NLs::PathExist});
+            UNIT_ASSERT(describeResult.GetPathDescription().HasExternalTableDescription());
+            const auto& externalTableDescription = describeResult.GetPathDescription().GetExternalTableDescription();
+            UNIT_ASSERT_VALUES_EQUAL(externalTableDescription.GetName(), "ExternalTable");
+            UNIT_ASSERT_VALUES_EQUAL(externalTableDescription.GetDataSourcePath(), "/MyRoot/ExternalDataSource");
+            UNIT_ASSERT_VALUES_EQUAL(externalTableDescription.GetLocation(), "/new_location");
+            UNIT_ASSERT_VALUES_EQUAL(externalTableDescription.GetSourceType(), "ObjectStorage");
+            UNIT_ASSERT_VALUES_EQUAL(externalTableDescription.GetVersion(), 2);
+            auto& columns = externalTableDescription.GetColumns();
+            UNIT_ASSERT_VALUES_EQUAL(columns.size(), 2);
+            UNIT_ASSERT_VALUES_EQUAL(columns.Get(0).GetName(), "key");
+            UNIT_ASSERT_VALUES_EQUAL(columns.Get(0).GetType(), "Uint64");
+            UNIT_ASSERT_VALUES_EQUAL(columns.Get(0).GetNotNull(), false);
+            UNIT_ASSERT_VALUES_EQUAL(columns.Get(1).GetName(), "value");
+            UNIT_ASSERT_VALUES_EQUAL(columns.Get(1).GetType(), "Uint64");
+            UNIT_ASSERT_VALUES_EQUAL(columns.Get(1).GetNotNull(), false);
+        }
+    }
+
+    Y_UNIT_TEST(CreateExternalTableWithOrReplaceShouldFailIfFeatureFlagIsNotSet) {
+        TTestBasicRuntime runtime;
+        TTestEnv env(runtime, TTestEnvOptions().EnableReplaceIfExists(false));
+        ui64 txId = 100;
+
+        CreateExternalDataSource(runtime, env, ++txId);
+        TestCreateExternalTable(runtime, ++txId, "/MyRoot", R"(
+                Name: "ExternalTable"
+                SourceType: "General"
+                DataSourcePath: "/MyRoot/ExternalDataSource"
+                Location: "/"
+                Columns { Name: "key" Type: "Uint64" }
+                ReplaceIfExists: true
+            )", {{NKikimrScheme::StatusPreconditionFailed, "Unsupported: feature flag EnableReplaceIfExists is off"}});
+
+        env.TestWaitNotification(runtime, txId);
+
+        TestLs(runtime, "/MyRoot/ExternalTable", false, NLs::PathNotExist);
+    }
 }