diff --git a/src/cryptography/hazmat/bindings/openssl/ssl.py b/src/cryptography/hazmat/bindings/openssl/ssl.py
index b182180..4a824ae 100644
--- a/src/cryptography/hazmat/bindings/openssl/ssl.py
+++ b/src/cryptography/hazmat/bindings/openssl/ssl.py
@@ -211,6 +211,9 @@
 int SSL_CTX_use_PrivateKey(SSL_CTX *, EVP_PKEY *);
 int SSL_CTX_use_PrivateKey_file(SSL_CTX *, const char *, int);
 int SSL_CTX_check_private_key(const SSL_CTX *);
+void SSL_CTX_set_cert_verify_callback(SSL_CTX *,
+                                      int (*)(X509_STORE_CTX *,void *),
+                                      void *);
 
 void SSL_CTX_set_cert_store(SSL_CTX *, X509_STORE *);
 X509_STORE *SSL_CTX_get_cert_store(const SSL_CTX *);