diff --git a/gnu/packages/ruby.scm b/gnu/packages/ruby.scm
index ac852f54b8..00b24b26f4 100644
--- a/gnu/packages/ruby.scm
+++ b/gnu/packages/ruby.scm
@@ -2882,7 +2882,7 @@ (define-public ruby-pg
        ("ruby-hoe" ,ruby-hoe)
        ("ruby-rspec" ,ruby-rspec)))
     (inputs
-     `(("postgresql" ,postgresql)))
+     `(("postgresql" ,postgresql-9.6)))
     (synopsis "Ruby interface to PostgreSQL")
     (description "Pg is the Ruby interface to the PostgreSQL RDBMS.  It works
 with PostgreSQL 8.4 and later.")