diff --git a/c/src/ada-tests/support/test_support.adb b/c/src/ada-tests/support/test_support.adb
index d5ab4b40ba..b3e3a2d86c 100644
--- a/c/src/ada-tests/support/test_support.adb
+++ b/c/src/ada-tests/support/test_support.adb
@@ -207,7 +207,7 @@ package body Test_Support is
    ) return RTEMS.Unsigned32 is
    begin
 
-      return RTEMS.Get_Index( TID ) - 
+      return RTEMS.Get_Index( TID ) - 1 -
         RTEMS.Configuration.RTEMS_API_Configuration.Number_Of_Initialization_Tasks;
 
    end Task_Number;