diff --git a/ydb/core/kqp/ut/common/kqp_ut_common.cpp b/ydb/core/kqp/ut/common/kqp_ut_common.cpp
index 9997745b5da9..2fbf5042588e 100644
--- a/ydb/core/kqp/ut/common/kqp_ut_common.cpp
+++ b/ydb/core/kqp/ut/common/kqp_ut_common.cpp
@@ -129,7 +129,6 @@ TKikimrRunner::TKikimrRunner(const TKikimrSettings& settings) {
     ServerSettings->SetFrFactory(&UdfFrFactory);
     ServerSettings->SetEnableNotNullColumns(true);
     ServerSettings->SetEnableMoveIndex(true);
-    ServerSettings->SetEnableUniqConstraint(true);
     ServerSettings->SetUseRealThreads(settings.UseRealThreads);
     ServerSettings->SetEnableTablePgTypes(true);
     ServerSettings->SetEnablePgSyntax(true);
diff --git a/ydb/core/protos/feature_flags.proto b/ydb/core/protos/feature_flags.proto
index 7130ce3a81f4..6b2d1ff4f982 100644
--- a/ydb/core/protos/feature_flags.proto
+++ b/ydb/core/protos/feature_flags.proto
@@ -116,7 +116,7 @@ message TFeatureFlags {
     optional bool EnableIcNodeCache = 101 [default = true];
     optional bool EnableTempTables = 102 [default = false];
     optional bool SuppressCompatibilityCheck = 103 [default = false];
-    optional bool EnableUniqConstraint = 104 [default = false];
+    optional bool EnableUniqConstraint = 104 [default = true];
     optional bool EnableChangefeedDebeziumJsonFormat = 105 [default = false];
     optional bool EnableStatistics = 106 [default = true];
     optional bool EnableUuidAsPrimaryKey = 107 [default = true];