diff --git a/src/backend/distributed/planner/multi_physical_planner.c b/src/backend/distributed/planner/multi_physical_planner.c
index be6caf0e2..f488a1cd5 100644
--- a/src/backend/distributed/planner/multi_physical_planner.c
+++ b/src/backend/distributed/planner/multi_physical_planner.c
@@ -4573,7 +4573,8 @@ RowModifyLevelForQuery(Query *query)
 	}
 
 	if (commandType == CMD_UPDATE ||
-		commandType == CMD_DELETE)
+		commandType == CMD_DELETE ||
+		commandType == CMD_MERGE)
 	{
 		return ROW_MODIFY_NONCOMMUTATIVE;
 	}
diff --git a/src/test/regress/expected/isolation_merge.out b/src/test/regress/expected/isolation_merge.out
new file mode 100644
index 000000000..d78c46c64
--- /dev/null
+++ b/src/test/regress/expected/isolation_merge.out
@@ -0,0 +1,147 @@
+Parsed test spec with 2 sessions
+
+starting permutation: s1-begin s1-upd-ins s2-result s1-commit s2-result
+step s1-begin: BEGIN;
+step s1-upd-ins: MERGE INTO prept USING preps ON prept.t1 = preps.s1
+   WHEN MATCHED THEN UPDATE SET t2 = t2 + 1
+   WHEN NOT MATCHED THEN INSERT VALUES(s1, s2);
+
+step s2-result: SELECT * FROM prept ORDER BY 1;
+ t1|t2
+---------------------------------------------------------------------
+100| 0
+(1 row)
+
+step s1-commit: COMMIT;
+step s2-result: SELECT * FROM prept ORDER BY 1;
+ t1|t2
+---------------------------------------------------------------------
+100| 1
+200| 0
+(2 rows)
+
+
+starting permutation: s1-begin s1-upd-ins s2-begin s2-upd-del s1-commit s2-commit s2-result
+step s1-begin: BEGIN;
+step s1-upd-ins: MERGE INTO prept USING preps ON prept.t1 = preps.s1
+   WHEN MATCHED THEN UPDATE SET t2 = t2 + 1
+   WHEN NOT MATCHED THEN INSERT VALUES(s1, s2);
+
+step s2-begin: BEGIN;
+step s2-upd-del: MERGE INTO prept USING preps ON prept.t1 = preps.s1
+   WHEN MATCHED AND prept.t2 = 0 THEN DELETE
+   WHEN MATCHED THEN UPDATE SET t2 = t2 + 1;
+ <waiting ...>
+step s1-commit: COMMIT;
+step s2-upd-del: <... completed>
+step s2-commit: COMMIT;
+step s2-result: SELECT * FROM prept ORDER BY 1;
+ t1|t2
+---------------------------------------------------------------------
+100| 2
+(1 row)
+
+
+starting permutation: s2-begin s2-upd-del s1-begin s1-upd-ins s2-commit s1-commit s2-result
+step s2-begin: BEGIN;
+step s2-upd-del: MERGE INTO prept USING preps ON prept.t1 = preps.s1
+   WHEN MATCHED AND prept.t2 = 0 THEN DELETE
+   WHEN MATCHED THEN UPDATE SET t2 = t2 + 1;
+
+step s1-begin: BEGIN;
+step s1-upd-ins: MERGE INTO prept USING preps ON prept.t1 = preps.s1
+   WHEN MATCHED THEN UPDATE SET t2 = t2 + 1
+   WHEN NOT MATCHED THEN INSERT VALUES(s1, s2);
+ <waiting ...>
+step s2-commit: COMMIT;
+step s1-upd-ins: <... completed>
+step s1-commit: COMMIT;
+step s2-result: SELECT * FROM prept ORDER BY 1;
+ t1|t2
+---------------------------------------------------------------------
+100| 0
+200| 0
+(2 rows)
+
+
+starting permutation: s1-begin s1-upd-ins s2-begin s2-upd s1-commit s2-commit s2-result
+step s1-begin: BEGIN;
+step s1-upd-ins: MERGE INTO prept USING preps ON prept.t1 = preps.s1
+   WHEN MATCHED THEN UPDATE SET t2 = t2 + 1
+   WHEN NOT MATCHED THEN INSERT VALUES(s1, s2);
+
+step s2-begin: BEGIN;
+step s2-upd: MERGE INTO prept USING preps ON prept.t1 = preps.s1
+   WHEN MATCHED THEN UPDATE SET t2 = t2 + 1;
+ <waiting ...>
+step s1-commit: COMMIT;
+step s2-upd: <... completed>
+step s2-commit: COMMIT;
+step s2-result: SELECT * FROM prept ORDER BY 1;
+ t1|t2
+---------------------------------------------------------------------
+100| 2
+200| 1
+(2 rows)
+
+
+starting permutation: s2-begin s2-ins s1-begin s1-del s2-upd s2-result s2-commit s1-commit s2-result
+step s2-begin: BEGIN;
+step s2-ins: MERGE INTO prept USING preps ON prept.t1 = preps.s1
+   WHEN NOT MATCHED THEN INSERT VALUES(s1, s2);
+
+step s1-begin: BEGIN;
+step s1-del: MERGE INTO prept USING preps ON prept.t1 = preps.s1
+   WHEN MATCHED THEN DELETE;
+ <waiting ...>
+step s2-upd: MERGE INTO prept USING preps ON prept.t1 = preps.s1
+   WHEN MATCHED THEN UPDATE SET t2 = t2 + 1;
+
+step s2-result: SELECT * FROM prept ORDER BY 1;
+ t1|t2
+---------------------------------------------------------------------
+100| 1
+200| 1
+(2 rows)
+
+step s2-commit: COMMIT;
+step s1-del: <... completed>
+step s1-commit: COMMIT;
+step s2-result: SELECT * FROM prept ORDER BY 1;
+t1|t2
+---------------------------------------------------------------------
+(0 rows)
+
+
+starting permutation: s1-begin s1-del-ins s2-begin s2-upd s1-result s1-ins s1-commit s2-upd s2-commit s2-result
+step s1-begin: BEGIN;
+step s1-del-ins: MERGE INTO prept USING preps ON prept.t1 = preps.s1
+   WHEN MATCHED THEN DELETE
+   WHEN NOT MATCHED THEN INSERT VALUES(s1, s2);
+
+step s2-begin: BEGIN;
+step s2-upd: MERGE INTO prept USING preps ON prept.t1 = preps.s1
+   WHEN MATCHED THEN UPDATE SET t2 = t2 + 1;
+ <waiting ...>
+step s1-result: SELECT * FROM prept ORDER BY 1;
+ t1|t2
+---------------------------------------------------------------------
+200| 0
+(1 row)
+
+step s1-ins: MERGE INTO prept USING preps ON prept.t1 = preps.s1
+   WHEN NOT MATCHED THEN INSERT VALUES(s1, s2);
+
+step s1-commit: COMMIT;
+step s2-upd: <... completed>
+step s2-upd: MERGE INTO prept USING preps ON prept.t1 = preps.s1
+   WHEN MATCHED THEN UPDATE SET t2 = t2 + 1;
+
+step s2-commit: COMMIT;
+step s2-result: SELECT * FROM prept ORDER BY 1;
+ t1|t2
+---------------------------------------------------------------------
+100| 2
+200| 2
+(2 rows)
+
diff --git a/src/test/regress/expected/isolation_merge_0.out b/src/test/regress/expected/isolation_merge_0.out
new file mode 100644
index 000000000..3b43a25e6
--- /dev/null
+++ b/src/test/regress/expected/isolation_merge_0.out
@@ -0,0 +1,5 @@
+Parsed test spec with 2 sessions
+
+starting permutation: s1-begin s1-upd-ins s2-result s1-commit s2-result
+setup failed: ERROR:  MERGE is not supported on PG versions below 15
+CONTEXT:  PL/pgSQL function inline_code_block line XX at RAISE
diff --git a/src/test/regress/expected/isolation_merge_replicated.out b/src/test/regress/expected/isolation_merge_replicated.out
new file mode 100644
index 000000000..e7e8b36ba
--- /dev/null
+++ b/src/test/regress/expected/isolation_merge_replicated.out
@@ -0,0 +1,26 @@
+Parsed test spec with 2 sessions
+
+starting permutation: s1-begin s1-upd-ins s2-begin s2-update s1-commit s2-commit s1-result s2-result
+step s1-begin: BEGIN;
+step s1-upd-ins: MERGE INTO prept USING preps ON prept.t1 = preps.s1
+   WHEN MATCHED THEN UPDATE SET t2 = t2 + 1
+   WHEN NOT MATCHED THEN INSERT VALUES(s1, s2);
+step s2-begin: BEGIN;
+step s2-update: UPDATE preps SET s2 = s2 + 1; <waiting ...>
+step s1-commit: COMMIT;
+step s2-update: <... completed>
+step s2-commit: COMMIT;
+step s1-result: SELECT * FROM preps ORDER BY 1;
+ s1|s2
+---------------------------------------------------------------------
+100| 1
+200| 1
+(2 rows)
+
+step s2-result: SELECT * FROM prept ORDER BY 1;
+ t1|t2
+---------------------------------------------------------------------
+100| 1
+200| 0
+(2 rows)
+
diff --git a/src/test/regress/expected/isolation_merge_replicated_0.out b/src/test/regress/expected/isolation_merge_replicated_0.out
new file mode 100644
index 000000000..51161dfb7
--- /dev/null
+++ b/src/test/regress/expected/isolation_merge_replicated_0.out
@@ -0,0 +1,5 @@
+Parsed test spec with 2 sessions
+
+starting permutation: s1-begin s1-upd-ins s2-begin s2-update s1-commit s2-commit s1-result s2-result
+setup failed: ERROR:  MERGE is not supported on PG versions below 15
+CONTEXT:  PL/pgSQL function inline_code_block line XX at RAISE
diff --git a/src/test/regress/isolation_schedule b/src/test/regress/isolation_schedule
index 90d1463ad..ca893ba8d 100644
--- a/src/test/regress/isolation_schedule
+++ b/src/test/regress/isolation_schedule
@@ -107,4 +107,10 @@ test: isolation_multiuser_locking
 test: isolation_acquire_distributed_locks
 test: isolation_concurrent_move_create_table
 
+# MERGE
+test: isolation_merge
+test: isolation_merge_replicated
+
+
+# Note: Always keep this test at the end
 test: isolation_check_mx
diff --git a/src/test/regress/spec/isolation_merge.spec b/src/test/regress/spec/isolation_merge.spec
new file mode 100644
index 000000000..042ce9155
--- /dev/null
+++ b/src/test/regress/spec/isolation_merge.spec
@@ -0,0 +1,92 @@
+//
+// How we organize this isolation test spec, is explained at README.md file in this directory.
+//
+
+// create distributed tables to test behavior of MERGE in concurrent operations
+setup
+{
+	DO
+	$do$
+	DECLARE ver int;
+	BEGIN
+	  SELECT substring(version(), '\d+')::int into ver;
+	  IF (ver < 15)
+	  THEN
+	    RAISE EXCEPTION 'MERGE is not supported on PG versions below 15';
+	  END IF;
+	  END
+	$do$;
+
+	SET citus.shard_replication_factor TO 1;
+	SELECT 1 FROM master_add_node('localhost', 57637);
+	SELECT 1 FROM master_add_node('localhost', 57638);
+
+	CREATE TABLE prept(t1 int, t2 int);
+	CREATE TABLE preps(s1 int, s2 int);
+	SELECT create_distributed_table('prept', 't1'), create_distributed_table('preps', 's1');
+	INSERT INTO prept VALUES(100, 0);
+	INSERT INTO preps VALUES(100, 0);
+	INSERT INTO preps VALUES(200, 0);
+}
+
+// drop distributed tables
+teardown
+{
+	DROP TABLE IF EXISTS prept CASCADE;
+	DROP TABLE IF EXISTS preps CASCADE;
+}
+
+// session 1
+session "s1"
+
+step "s1-begin" { BEGIN; }
+
+step "s1-upd-ins" { MERGE INTO prept USING preps ON prept.t1 = preps.s1
+			WHEN MATCHED THEN UPDATE SET t2 = t2 + 1
+			WHEN NOT MATCHED THEN INSERT VALUES(s1, s2);
+		}
+
+step "s1-del-ins" { MERGE INTO prept USING preps ON prept.t1 = preps.s1
+			WHEN MATCHED THEN DELETE
+			WHEN NOT MATCHED THEN INSERT VALUES(s1, s2);
+		}
+
+step "s1-del" { MERGE INTO prept USING preps ON prept.t1 = preps.s1
+			WHEN MATCHED THEN DELETE;
+		}
+
+step "s1-ins" { MERGE INTO prept USING preps ON prept.t1 = preps.s1
+			WHEN NOT MATCHED THEN INSERT VALUES(s1, s2);
+		}
+
+step "s1-commit" { COMMIT; }
+step "s1-result" { SELECT * FROM prept ORDER BY 1; }
+
+// session 2
+session "s2"
+
+step "s2-begin" { BEGIN; }
+
+step "s2-upd-del" { MERGE INTO prept USING preps ON prept.t1 = preps.s1
+			WHEN MATCHED AND prept.t2 = 0 THEN DELETE
+			WHEN MATCHED THEN UPDATE SET t2 = t2 + 1;
+		}
+
+step "s2-upd" { MERGE INTO prept USING preps ON prept.t1 = preps.s1
+			WHEN MATCHED THEN UPDATE SET t2 = t2 + 1;
+		}
+
+step "s2-ins" { MERGE INTO prept USING preps ON prept.t1 = preps.s1
+			WHEN NOT MATCHED THEN INSERT VALUES(s1, s2);
+		}
+
+step "s2-commit" { COMMIT; }
+step "s2-result" { SELECT * FROM prept ORDER BY 1; }
+
+// permutations - MERGE vs MERGE
+permutation "s1-begin" "s1-upd-ins" "s2-result" "s1-commit" "s2-result"
+permutation "s1-begin" "s1-upd-ins" "s2-begin" "s2-upd-del" "s1-commit" "s2-commit" "s2-result"
+permutation "s2-begin" "s2-upd-del" "s1-begin" "s1-upd-ins" "s2-commit" "s1-commit" "s2-result"
+permutation "s1-begin" "s1-upd-ins" "s2-begin" "s2-upd" "s1-commit" "s2-commit" "s2-result"
+permutation "s2-begin" "s2-ins" "s1-begin" "s1-del" "s2-upd" "s2-result" "s2-commit" "s1-commit" "s2-result"
+permutation "s1-begin" "s1-del-ins" "s2-begin" "s2-upd" "s1-result" "s1-ins" "s1-commit" "s2-upd" "s2-commit" "s2-result"
diff --git a/src/test/regress/spec/isolation_merge_replicated.spec b/src/test/regress/spec/isolation_merge_replicated.spec
new file mode 100644
index 000000000..a586bdfa1
--- /dev/null
+++ b/src/test/regress/spec/isolation_merge_replicated.spec
@@ -0,0 +1,58 @@
+//
+// How we organize this isolation test spec, is explained at README.md file in this directory.
+//
+
+// create distributed tables to test behavior of MERGE in concurrent operations
+setup
+{
+	DO
+	$do$
+	DECLARE ver int;
+	BEGIN
+	  SELECT substring(version(), '\d+')::int into ver;
+	  IF (ver < 15)
+	  THEN
+	    RAISE EXCEPTION 'MERGE is not supported on PG versions below 15';
+	  END IF;
+	  END
+	$do$;
+
+	SET citus.shard_replication_factor TO 2;
+	SELECT 1 FROM master_add_node('localhost', 57637);
+	SELECT 1 FROM master_add_node('localhost', 57638);
+
+	CREATE TABLE prept(t1 int, t2 int);
+	CREATE TABLE preps(s1 int, s2 int);
+	SELECT create_distributed_table('prept', 't1'), create_distributed_table('preps', 's1');
+	INSERT INTO prept VALUES(100, 0);
+	INSERT INTO preps VALUES(100, 0);
+	INSERT INTO preps VALUES(200, 0);
+}
+
+// drop distributed tables
+teardown
+{
+	DROP TABLE IF EXISTS prept CASCADE;
+	DROP TABLE IF EXISTS preps CASCADE;
+}
+
+// session 1
+session "s1"
+
+step "s1-begin" { BEGIN; }
+step "s1-upd-ins" { MERGE INTO prept USING preps ON prept.t1 = preps.s1
+			WHEN MATCHED THEN UPDATE SET t2 = t2 + 1
+			WHEN NOT MATCHED THEN INSERT VALUES(s1, s2); }
+step "s1-result" { SELECT * FROM preps ORDER BY 1; }
+step "s1-commit" { COMMIT; }
+
+// session 2
+session "s2"
+
+step "s2-begin" { BEGIN; }
+step "s2-update" { UPDATE preps SET s2 = s2 + 1; }
+step "s2-commit" { COMMIT; }
+step "s2-result" { SELECT * FROM prept ORDER BY 1; }
+
+// permutations - MERGE vs UPDATE (on source)
+permutation "s1-begin" "s1-upd-ins" "s2-begin" "s2-update" "s1-commit" "s2-commit" "s1-result" "s2-result"