diff --git a/crypto/bn/bn_lcl.h b/crypto/bn/bn_lcl.h
index b5be6fc814..5fb3814554 100644
--- a/crypto/bn/bn_lcl.h
+++ b/crypto/bn/bn_lcl.h
@@ -177,8 +177,8 @@ int RAND_bytes(unsigned char *buf, int num);
         do { \
                 const BIGNUM *_bnum2 = (a); \
                 if (_bnum2 != NULL) { \
-                        OPENSSL_assert((_bnum2->top == 0) || \
-                                (_bnum2->d[_bnum2->top - 1] != 0)); \
+                        OPENSSL_assert(((_bnum2->top == 0) && !_bnum2->neg) || \
+                                (_bnum2->top && (_bnum2->d[_bnum2->top - 1] != 0))); \
                         bn_pollute(_bnum2); \
                 } \
         } while(0)