diff --git a/include/openssl/base.h b/include/openssl/base.h
index de14ff4..e4ab531 100644
--- a/include/openssl/base.h
+++ b/include/openssl/base.h
@@ -109,6 +109,7 @@
 
 #define OPENSSL_IS_BORINGSSL
 #define OPENSSL_VERSION_NUMBER 0x10002000
+#define SSLEAY_VERSION_NUMBER OPENSSL_VERSION_NUMBER
 
 #if defined(BORINGSSL_SHARED_LIBRARY)