diff --git a/lib/angstrom.ml b/lib/angstrom.ml
index cf3b195..987b294 100644
--- a/lib/angstrom.ml
+++ b/lib/angstrom.ml
@@ -342,7 +342,7 @@ let rec count_while ~init ~f ~with_buffer =
       let succ' input' pos' more' =
         (count_while ~init:init' ~f ~with_buffer).run input' pos' more' fail succ
       and fail' input' pos' more' =
-        succ input' pos' more' (Input.apply input' pos' init' ~f:with_buffer)
+        succ input' (pos' + init') more' (Input.apply input' pos' init' ~f:with_buffer)
       in
       prompt input pos fail' succ'
   }
@@ -370,7 +370,7 @@ let rec count_while1 ~f ~with_buffer =
       let succ' input' pos' more' =
         (count_while ~init:len ~f ~with_buffer).run input' pos' more' fail succ
       and fail' input' pos' more' =
-        succ input' pos' more' (Input.apply input' pos' len ~f:with_buffer)
+        succ input' (pos' + len) more' (Input.apply input' pos' len ~f:with_buffer)
       in
       prompt input pos fail' succ'
   }
diff --git a/lib_test/test_angstrom.ml b/lib_test/test_angstrom.ml
index 70b5e10..8f6ec54 100644
--- a/lib_test/test_angstrom.ml
+++ b/lib_test/test_angstrom.ml
@@ -341,6 +341,14 @@ let incremental =
         (string "thi" *> string "st" *> commit *> string "hat") ["thi"; "st"; "hat"] "hat";
     end ]
 
+let count_while_regression =
+  [ "proper position set after count_while", `Quick, begin fun () ->
+    check_s ~msg:"take_while then eof"
+      (take_while (fun _ -> true) <* end_of_input) ["asdf"; ""] "asdf";
+    check_s ~msg:"take_while1 then eof"
+      (take_while1 (fun _ -> true) <* end_of_input) ["asdf"; ""] "asdf";
+  end ]
+
 let () =
   Alcotest.run "test suite"
     [ "basic constructors"    , basic_constructors
@@ -350,4 +358,6 @@ let () =
     ; "applicative interface" , applicative
     ; "alternative"           , alternative
     ; "combinators"           , combinators
-    ; "incremental input"     , incremental ]
+    ; "incremental input"     , incremental 
+    ; "count_while regression", count_while_regression
+  ]