diff --git a/Jamfile b/Jamfile
index e4ab659753..d435a2a714 100644
--- a/Jamfile
+++ b/Jamfile
@@ -1,3 +1,8 @@
+if ! [ Match "(.*)-haiku-(.*)" : $(JAMVERSION) ] {
+	Exit "You can only build Haiku with Haiku's Jam, not Perforce Jam or"
+		"some other variant (you are using $(JAMVERSION))." ;
+}
+
 SubDir HAIKU_TOP ;
 
 NotFile doc_files ;