diff --git a/doc/src/sgml/pgcrypto.sgml b/doc/src/sgml/pgcrypto.sgml
index 7e726cc891..8ab92c4e8f 100644
--- a/doc/src/sgml/pgcrypto.sgml
+++ b/doc/src/sgml/pgcrypto.sgml
@@ -63,7 +63,7 @@ $$ LANGUAGE SQL STRICT IMMUTABLE;
 
 <synopsis>
 hmac(data text, key text, type text) returns bytea
-hmac(data bytea, key text, type text) returns bytea
+hmac(data bytea, key bytea, type text) returns bytea
 </synopsis>
 
    <para>