diff --git a/Modules/mmapmodule.c b/Modules/mmapmodule.c
index 8cf0e87..62d934c 100644
--- a/Modules/mmapmodule.c
+++ b/Modules/mmapmodule.c
@@ -1388,6 +1388,11 @@
             }
 
             size = (((PY_LONG_LONG) high) << 32) + low;
+            if (size == 0) {
+                PyErr_SetString(PyExc_ValueError,
+                                "cannot mmap an empty file");
+                return NULL;
+            }
             if (offset >= size) {
                 PyErr_SetString(PyExc_ValueError,
                                 "mmap offset is greater than file size");