diff --git a/doc/src/sgml/pgcrypto.sgml b/doc/src/sgml/pgcrypto.sgml
index 7e726cc8910060f7f56018c8bcb4dea8ffdac104..8ab92c4e8f4bfe02bf65b8bfbdc33ccd9264c7da 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>