diff --git a/ein-cell.el b/ein-cell.el
index 438b0ba9..035a421f 100644
--- a/ein-cell.el
+++ b/ein-cell.el
@@ -69,6 +69,7 @@
                         ;;        make this slot typed.
                         ;; :type integer
                         )
+   (collapsed :initarg :collapsed :initform nil :type boolean)
    (running :initarg :running :initform nil :type boolean)))
 
 (defclass ein:textcell (ein:basecell)
@@ -107,6 +108,9 @@
   (ein:oset-if-empty cell :input (plist-get data :input))
   (ein:aif (plist-get data :prompt_number)
       (ein:oset-if-empty cell :input-prompt-number it))
+  (ein:oset-if-empty cell :collapsed
+                     (let ((v (plist-get data :collapsed)))
+                       (if (eql v json-false) nil v)))
   cell)
 
 (defmethod ein:cell-init ((cell ein:textcell) data)
@@ -292,14 +296,15 @@ A specific node can be specified using optional ARGS."
 (defvar ein:cell-output-dynamic nil)
 
 (defun ein:cell-insert-output (index cell)
-  (let ((out (nth index (oref cell :outputs)))
-        (dynamic ein:cell-output-dynamic))
-    (ein:case-equal (plist-get out :output_type)
-      (("pyout")        (ein:cell-append-pyout        cell out dynamic))
-      (("pyerr")        (ein:cell-append-pyerr        cell out))
-      (("display_data") (ein:cell-append-display-data cell out dynamic))
-      (("stream")       (ein:cell-append-stream       cell out))))
-  (ein:insert-read-only "\n"))
+  (unless (oref cell :collapsed)
+    (let ((out (nth index (oref cell :outputs)))
+          (dynamic ein:cell-output-dynamic))
+      (ein:case-equal (plist-get out :output_type)
+        (("pyout")        (ein:cell-append-pyout        cell out dynamic))
+        (("pyerr")        (ein:cell-append-pyerr        cell out))
+        (("display_data") (ein:cell-append-display-data cell out dynamic))
+        (("stream")       (ein:cell-append-stream       cell out))))
+    (ein:insert-read-only "\n")))
 
 (defun ein:cell-insert-footer ()
   (ein:insert-read-only "\n"))
@@ -353,6 +358,13 @@ A specific node can be specified using optional ARGS."
   ;; FIXME: change the appearance of the cell
   (oset cell :running running))
 
+(defmethod ein:cell-toggle-output ((cell ein:codecell))
+  "Toggle `:collapsed' slot of CELL and invalidate output ewoc nodes."
+  (oset cell :collapsed (not (oref cell :collapsed)))
+  (apply #'ewoc-invalidate
+         (oref cell :ewoc)
+         (ein:cell-element-get cell :output)))
+
 (defun ein:cell-set-input-prompt (cell &optional number)
   (oset cell :input-prompt-number number)
   (let ((inhibit-read-only t)
@@ -527,8 +539,7 @@ A specific node can be specified using optional ARGS."
           `((prompt_number . ,it)))
     (outputs . ,(apply #'vector (oref cell :outputs)))
     (language . "python")
-    ;; FIXME: implement `collapsed'
-    (collapsed . ,json-false)))
+    (collapsed . ,(if (oref cell :collapsed) t json-false))))
 
 (defmethod ein:cell-to-json ((cell ein:textcell))
   `((cell_type . ,(oref cell :cell-type))
diff --git a/ein-notebook.el b/ein-notebook.el
index f2018d7a..4ae6d501 100644
--- a/ein-notebook.el
+++ b/ein-notebook.el
@@ -349,6 +349,18 @@ when the prefix argument is given."
         (ein:cell-goto it)
       (ein:log 'warn "No previous cell"))))
 
+
+;;; Cell collapsing and output clearing
+
+(defun ein:notebook-toggle-output (notebook cell)
+  (ein:cell-toggle-output cell)
+  (setf (ein:$notebook-dirty notebook) t))
+
+(defun ein:notebook-toggle-output-command ()
+  (interactive)
+  (ein:notebook-with-cell #'ein:codecell-p
+    (ein:notebook-toggle-output ein:notebook cell)))
+
 
 ;;; Kernel related things
 
@@ -677,6 +689,7 @@ NAME is any non-empty string that does not contain '/' or '\\'."
   (let ((map (make-sparse-keymap)))
     (define-key map "\C-c\C-r" 'ein:notebook-render)
     (define-key map "\C-c\C-c" 'ein:notebook-execute-current-cell)
+    (define-key map "\C-c\C-e" 'ein:notebook-toggle-output-command)
     (define-key map "\C-c\C-d" 'ein:notebook-delete-cell-command)
     (define-key map "\C-c\C-k" 'ein:notebook-kill-cell-command)
     (define-key map "\C-c\M-w" 'ein:notebook-copy-cell-command)