diff --git a/tools/python/xen/xend/balloon.py b/tools/python/xen/xend/balloon.py
index 56c0e75e56..63f1f7eb42 100644
--- a/tools/python/xen/xend/balloon.py
+++ b/tools/python/xen/xend/balloon.py
@@ -152,7 +152,7 @@ def free(required):
                            'I cannot release any more.  I need %d MiB but '
                            'only have %d.') %
                           (need_mem, free_mem))
-        elif new_alloc >= dom0_min_mem:
+        elif new_alloc < dom0_min_mem:
             raise VmError(
                 ('I need %d MiB, but dom0_min_mem is %d and shrinking to '
                  '%d MiB would leave only %d MiB free.') %