diff --git a/src/Makefile b/src/Makefile
index ca4911c67..dcc0259c8 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -79,7 +79,7 @@ endif
 REDIS_CC=$(QUIET_CC)$(CC) $(FINAL_CFLAGS)
 REDIS_LD=$(QUIET_LINK)$(CC) $(FINAL_LDFLAGS)
 
-PREFIX=? /usr/local
+PREFIX?=/usr/local
 INSTALL_BIN= $(PREFIX)/bin
 INSTALL= cp -pf