diff --git a/bitbake/lib/bb/build.py b/bitbake/lib/bb/build.py
index 7571421d71..a83de8d73e 100644
--- a/bitbake/lib/bb/build.py
+++ b/bitbake/lib/bb/build.py
@@ -815,6 +815,9 @@ def add_tasks(tasklist, d):
         task_deps['parents'][task] = []
         if 'deps' in flags:
             for dep in flags['deps']:
+                # Check and warn for "addtask task after foo" while foo does not exist
+                if not dep in tasklist:
+                    bb.warn('%s: dependent task %s does not exist' % (d.getVar('PN'), dep))
                 dep = d.expand(dep)
                 task_deps['parents'][task].append(dep)