diff --git a/libsrc/CRTM_Module.F90 b/libsrc/CRTM_Module.F90
index 92cad1e20..e936d1006 100644
--- a/libsrc/CRTM_Module.F90
+++ b/libsrc/CRTM_Module.F90
@@ -35,7 +35,8 @@ MODULE CRTM_Module
   USE CRTM_K_Matrix_Module
   ! ...The aerosol optical depth tool
   USE CRTM_AOD_Module
-
+  ! ...Planck Functions
+  USE CRTM_Planck_Functions
 
   ! Visibility
   ! ----------