diff --git a/hgext/split.py b/hgext/split.py
--- a/hgext/split.py
+++ b/hgext/split.py
@@ -108,6 +108,7 @@
         if len(ctx.parents()) > 1:
             raise error.Abort(_('cannot split a merge changeset'))
 
+        cmdutil.checkunfinished(repo)
         cmdutil.bailifchanged(repo)
 
         # Deactivate bookmark temporarily so it won't get moved unintentionally
diff --git a/tests/test-split.t b/tests/test-split.t
--- a/tests/test-split.t
+++ b/tests/test-split.t
@@ -91,6 +91,15 @@
   $ hg forget dirty
   $ rm dirty
 
+Cannot split while there's an unfinished operation
+
+  $ touch .hg/graftstate
+  $ hg split .
+  abort: graft in progress
+  (use 'hg graft --continue' or 'hg graft --stop' to stop)
+  [255]
+  $ rm .hg/graftstate
+
 Make a clean directory for future tests to build off of
 
   $ cp -R . ../clean