diff --git a/hgext3rd/sparse.py b/hgext3rd/sparse.py
--- a/hgext3rd/sparse.py
+++ b/hgext3rd/sparse.py
@@ -738,8 +738,9 @@
             oldstatus = repo.status()
 
             if any(pat.startswith('/') for pat in pats):
-                ui.warn(_('warning: paths cannot start with /, ignoring: %s\n')
-                          % ([pat for pat in pats if pat.startswith('/')]))
+                err = _('paths cannot start with /')
+                hint = _('do not use absolute paths')
+                raise error.Abort(err, hint=hint)
             elif include:
                 newinclude.update(pats)
             elif exclude:
diff --git a/tests/test-sparse.t b/tests/test-sparse.t
--- a/tests/test-sparse.t
+++ b/tests/test-sparse.t
@@ -28,11 +28,15 @@
 Absolute paths outside the repo should just be rejected
 
   $ hg sparse --include /foo/bar
-  warning: paths cannot start with /, ignoring: ['/foo/bar']
+  abort: paths cannot start with /
+  (do not use absolute paths)
+  [255]
   $ hg sparse --include '$TESTTMP/myrepo/hide'
 
   $ hg sparse --include '/root'
-  warning: paths cannot start with /, ignoring: ['/root']
+  abort: paths cannot start with /
+  (do not use absolute paths)
+  [255]
 
 Verify commiting while sparse includes other files