diff --git a/src/config.c b/src/config.c
index 8a5ad6c2..1bd678c7 100644
--- a/src/config.c
+++ b/src/config.c
@@ -241,6 +241,7 @@ void configSetCommand(redisClient *c) {
         if (getLongLongFromObject(o,&ll) == REDIS_ERR ||
             ll < 0) goto badfmt;
         server.maxmemory = ll;
+        if (server.maxmemory) freeMemoryIfNeeded();
     } else if (!strcasecmp(c->argv[2]->ptr,"timeout")) {
         if (getLongLongFromObject(o,&ll) == REDIS_ERR ||
             ll < 0 || ll > LONG_MAX) goto badfmt;