diff --git a/Makefile b/Makefile
index e99c1d322..da5c6947e 100644
--- a/Makefile
+++ b/Makefile
@@ -22,8 +22,8 @@ uninstall:
 	$(RM) `opam var bin`/$(EXECUTABLE)
 
 regression:
-	$(MAKE) clean check -j -C regression
-	$(MAKE) clean check -j -C stdlib/regression
+	$(MAKE) clean check -j8 -C regression
+	$(MAKE) clean check -j8 -C stdlib/regression
 	bash deploy_build.sh
 	$(MAKE) -C lama-compiler
 
diff --git a/regression/Makefile b/regression/Makefile
index fe16ceb24..cda54b4b7 100644
--- a/regression/Makefile
+++ b/regression/Makefile
@@ -19,8 +19,8 @@ ctest111:
 	@LAMA=../runtime $(LAMAC) test111.lama && cat test111.input | ./test111 > test111.log && diff test111.log orig/test111.log
 
 expr_tests:
-	make -j -C expressions
-	make -j -C deep-expressions
+	make -j8 -C expressions
+	make -j8 -C deep-expressions
 
 clean:
 	$(RM) test*.log *.s *.sm *~ $(TESTS) *.i $(DEBUG_FILES) test111