diff --git a/Makefile.am b/Makefile.am
index b4611fc..99c2a71 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,4 +1,4 @@
-EXTRA_DIST = MIGRATION
+EXTRA_DIST = MIGRATION libmodbus.spec
 SUBDIRS = modbus tests
 
 pkgconfigdir = $(libdir)/pkgconfig