diff --git a/src/diagnose.F90 b/src/diagnose.F90
index 073bd3c283487d3db44b92032f29012b6bae152c..a28d4105450d427e6bd3b177d5e6358576a4b6be 100644
--- a/src/diagnose.F90
+++ b/src/diagnose.F90
@@ -184,6 +184,7 @@ SUBROUTINE diagnose(kstep)
      CALL attach(fidres, TRIM(str),        "tmax",     tmax)
      CALL attach(fidres, TRIM(str),        "nrun",     nrun)
      CALL attach(fidres, TRIM(str),    "cpu_time",       -1)
+     CALL attach(fidres, TRIM(str),       "Nproc",num_procs)
 
      CALL grid_outputinputs(fidres, str)