diff --git a/mm/mm_heap/mm_sbrk.c b/mm/mm_heap/mm_sbrk.c
index a909d082c26..570021c07d6 100644
--- a/mm/mm_heap/mm_sbrk.c
+++ b/mm/mm_heap/mm_sbrk.c
@@ -141,7 +141,7 @@ FAR void *mm_sbrk(FAR struct mm_heap_s *heap, intptr_t incr,
        */
 
       bytesize = pgincr << MM_PGSHIFT;
-      if (brkaddr != 0)
+      if (brkaddr == 0)
         {
           /* No... then initialize it now */