diff --git a/hgext/git/dirstate.py b/hgext/git/dirstate.py
--- a/hgext/git/dirstate.py
+++ b/hgext/git/dirstate.py
@@ -301,8 +301,10 @@
     def drop(self, f):
         index = self.git.index
         index.read()
-        index.remove(pycompat.fsdecode(f))
-        index.write()
+        fs = pycompat.fsdecode(f)
+        if fs in index:
+            index.remove(fs)
+            index.write()
 
     def remove(self, f):
         index = self.git.index
diff --git a/tests/test-git-interop.t b/tests/test-git-interop.t
--- a/tests/test-git-interop.t
+++ b/tests/test-git-interop.t
@@ -270,3 +270,8 @@
   +++ b/beta	Mon Jan 01 00:00:11 2007 +0000
   @@ -0,0 +1,1 @@
   +beta
+
+
+Deleting files should also work (this was issue6398)
+  $ hg rm beta
+  $ hg ci -m 'remove beta'