diff --git a/openbsc/configure.ac b/openbsc/configure.ac
index 60601fe..5cd5d2d 100644
--- a/openbsc/configure.ac
+++ b/openbsc/configure.ac
@@ -73,6 +73,18 @@
 AM_CONDITIONAL(BUILD_MGCP_TRANSCODING, test "x$osmo_ac_mgcp_transcoding" = "xyes")
 AC_SUBST(osmo_ac_mgcp_transcoding)
 
+# Enable/disable 3G aka IuPS + IuCS support?
+AC_ARG_ENABLE([iu], [AS_HELP_STRING([--enable-iu], [Build 3G support, aka IuPS and IuCS interfaces])],
+    [osmo_ac_iu="$enableval"],[osmo_ac_iu="no"])
+if test "x$osmo_ac_iu" = "xyes" ; then
+    PKG_CHECK_MODULES(LIBASN1C, libasn1c) # TODO version?
+    PKG_CHECK_MODULES(LIBOSMORANAP, libosmo-ranap) # TODO version?
+    PKG_CHECK_MODULES(LIBOSMOSIGTRAN, libosmo-sigtran) # TODO version?
+    AC_DEFINE(BUILD_IU, 1, [Define if we want to build IuPS and IuCS interfaces support])
+fi
+AM_CONDITIONAL(BUILD_IU, test "x$osmo_ac_iu" = "xyes")
+AC_SUBST(osmo_ac_iu)
+
 
 found_libgtp=yes
 PKG_CHECK_MODULES(LIBGTP, libgtp >= 0.92, , found_libgtp=no)