diff --git a/OpenSSL/crypto/crypto.h b/OpenSSL/crypto/crypto.h
index 75961a7..fe25475 100644
--- a/OpenSSL/crypto/crypto.h
+++ b/OpenSSL/crypto/crypto.h
@@ -65,7 +65,7 @@
 
 #if defined(PY3) || defined(crypto_MODULE)
 
-extern crypto_X509_New_RETURN      crypto_X509_New      crypto_X509_New_PROTO;
+__declspec(dllexport) extern crypto_X509_New_RETURN      crypto_X509_New      crypto_X509_New_PROTO;
 extern crypto_X509Name_New_RETURN  crypto_X509Name_New  crypto_X509Name_New_PROTO;
 extern crypto_X509Req_New_RETURN   crypto_X509Req_New   crypto_X509Req_New_PROTO;
 extern crypto_X509Store_New_RETURN crypto_X509Store_New crypto_X509Store_New_PROTO;