diff --git a/var/spack/repos/builtin/packages/cernlib/package.py b/var/spack/repos/builtin/packages/cernlib/package.py
index 2417313120f..add2a5dacc7 100644
--- a/var/spack/repos/builtin/packages/cernlib/package.py
+++ b/var/spack/repos/builtin/packages/cernlib/package.py
@@ -22,6 +22,8 @@ class Cernlib(CMakePackage):
 
     depends_on("motif")
     depends_on("libx11")
+    depends_on("libxaw")
+    depends_on("libxt")
 
     def cmake_args(self):
         args = ["-DCERNLIB_BUILD_SHARED:BOOL=ON"]