diff --git a/Makefile b/Makefile
index 8608409292042a531aa2bc7c02e184ed987b9f83..ce53726c0024616bc706cf26eabcfa8fd36273f1 100644
--- a/Makefile
+++ b/Makefile
@@ -58,7 +58,7 @@ XFILES = dtifit ccops probtrack find_the_biggest medianfilter diff_pvm make_dyad
 FXFILES = reord_OM sausages replacevols fdt_matrix_ops probtrackx xfibres indexer
 
 
-RUNTCLS = Fdt
+RUNTCLS = Fdt Fdtx
 
 all: ${XFILES} ${FXFILES}