diff --git a/swig/ruby/Makefile.am b/swig/ruby/Makefile.am
index 9ecc010..12dd9af 100644
--- a/swig/ruby/Makefile.am
+++ b/swig/ruby/Makefile.am
@@ -13,7 +13,7 @@ install-data-local:
 endif
 
 ext/Makefile config.save:
-	$(RUBY) $(srcdir)/setup.rb config $(RUBY_CONFIG_OPTIONS)
+	$(RUBY) $(srcdir)/setup.rb config $(RUBY_CONFIG_OPTIONS) -- --with-comedilib-dir=../../..
 
 ext/comedi.so ext/comedi_ruby_wrap.o: ext/Makefile config.save $(srcdir)/ext/comedi_ruby_wrap.c
 	$(RUBY) $(srcdir)/setup.rb setup
diff --git a/swig/ruby/ext/extconf.rb b/swig/ruby/ext/extconf.rb
index 4702f02..15e67b9 100644
--- a/swig/ruby/ext/extconf.rb
+++ b/swig/ruby/ext/extconf.rb
@@ -1,3 +1,4 @@
 require 'mkmf'
+dir_config('comedilib')
 have_library('comedi')
 create_makefile("comedi")