diff --git a/lisp/ein-cell.el b/lisp/ein-cell.el
index f4ff4ed..211582f 100644
--- a/lisp/ein-cell.el
+++ b/lisp/ein-cell.el
@@ -187,7 +187,8 @@ See also: https://github.com/tkf/emacs-ipython-notebook/issues/94"
   "Notebook cell base class")
 
 (defclass ein:codecell (ein:basecell)
-  ((cell-type :initarg :cell-type :initform "code")
+  ((traceback :initform nil :initarg :traceback :type list)
+   (cell-type :initarg :cell-type :initform "code")
    (kernel :initarg :kernel :type ein:$kernel)
    (element-names :initform (:prompt :input :output :footer))
    (input-prompt-number :initarg :input-prompt-number
@@ -753,6 +754,7 @@ If END is non-`nil', return the location of next element."
   ;; instantaneously for now.
   (ein:log 'debug "cell-clear-output stdout=%s stderr=%s other=%s"
            stdout stderr other)
+  (oset cell :traceback nil)
   (let ((ewoc (oref cell :ewoc))
         (output-nodes (ein:cell-element-get cell :output)))
     (if (and stdout stderr other)
@@ -808,6 +810,20 @@ If END is non-`nil', return the location of next element."
            (intern (format "output-%s" (plist-get json :stream)))))))
 
 (defmethod ein:cell-append-output ((cell ein:codecell) json dynamic)
+  ;; When there is a python error, we actually get two identical tracebacks back
+  ;; from the kernel, one from the "shell" channel, and one from the "iopub"
+  ;; channel.  As a workaround, we remember the cell's traceback and ignore
+  ;; traceback outputs that are identical to the one we already have.
+  (let ((new-tb (plist-get json :traceback))
+        (old-tb (oref cell :traceback)))
+    (when (or
+           (null old-tb)
+           (null new-tb)
+           (not (equalp new-tb old-tb)))
+      (ein:cell-actually-append-output cell json dynamic))
+    (oset cell :traceback new-tb)))
+
+(defmethod ein:cell-actually-append-output ((cell ein:codecell) json dynamic)
   (ein:cell-expand cell)
   ;; (ein:flush-clear-timeout)
   (oset cell :outputs
@@ -1198,7 +1214,9 @@ prettified text thus be used instead of HTML type."
 
 (defmethod ein:cell-get-tb-data ((cell ein:codecell))
   (loop for out in (oref cell :outputs)
-        when (equal (plist-get out :output_type) "pyerr")
+        when (and
+              (not (null (plist-get out :traceback)))
+              (member (plist-get out :output_type) '("pyerr" "error")))
         return (plist-get out :traceback)))
 
 (provide 'ein-cell)