diff --git a/IPython/frontend/html/notebook/static/js/codecell.js b/IPython/frontend/html/notebook/static/js/codecell.js
index 71eb219..e7506c9 100644
--- a/IPython/frontend/html/notebook/static/js/codecell.js
+++ b/IPython/frontend/html/notebook/static/js/codecell.js
@@ -48,9 +48,10 @@ var IPython = (function (IPython) {
 
 
     CodeCell.prototype.handle_codemirror_keyevent = function (editor, event) {
-        // This method gets called in CodeMirror's onKeyDown/onKeyPress handlers and
-        // is used to provide custom key handling. Its return value is used to determine
-        // if CodeMirror should ignore the event: true = ignore, false = don't ignore.
+        // This method gets called in CodeMirror's onKeyDown/onKeyPress
+        // handlers and is used to provide custom key handling. Its return
+        // value is used to determine if CodeMirror should ignore the event:
+        // true = ignore, false = don't ignore.
         if (event.keyCode === 13 && (event.shiftKey || event.ctrlKey)) {
             // Always ignore shift-enter in CodeMirror as we handle it.
             return true;
@@ -59,8 +60,8 @@ var IPython = (function (IPython) {
             var cur = editor.getCursor();
             var pre_cursor = editor.getRange({line:cur.line,ch:0},cur).trim();
             if (pre_cursor === "") {
-                // Don't autocomplete if the part of the line before the cursor is empty.
-                // In this case, let CodeMirror handle indentation.
+                // Don't autocomplete if the part of the line before the cursor
+                // is empty.  In this case, let CodeMirror handle indentation.
                 return false;
             } else {
                 // Autocomplete the current line.
@@ -86,9 +87,19 @@ var IPython = (function (IPython) {
             } else {
                 return false;
             };
-        } else {
-            // keypress/keyup also trigger on TAB press, and we don't want to use those
-            // to disable tab completion.
+        } else if (event.keyCode === 76 && event.ctrlKey && event.shiftKey
+		   && event.type == 'keydown') {
+            // toggle line numbers with Ctrl-Shift-L
+	    if (this.code_mirror.getOption('lineNumbers') == false) {
+		this.code_mirror.setOption('lineNumbers', true);
+	    } else {
+		this.code_mirror.setOption('lineNumbers', false);
+	    }
+	    this.code_mirror.refresh()
+        }
+	else {
+            // keypress/keyup also trigger on TAB press, and we don't want to
+            // use those to disable tab completion.
             if (this.is_completing && event.keyCode !== 9) {
                 var ed_cur = editor.getCursor();
                 var cc_cur = this.completion_cursor;
@@ -470,4 +481,3 @@ var IPython = (function (IPython) {
 
     return IPython;
 }(IPython));
-
diff --git a/IPython/frontend/html/notebook/static/js/notebook.js b/IPython/frontend/html/notebook/static/js/notebook.js
index f5fcdc8..084e8f8 100644
--- a/IPython/frontend/html/notebook/static/js/notebook.js
+++ b/IPython/frontend/html/notebook/static/js/notebook.js
@@ -186,6 +186,7 @@ var IPython = (function (IPython) {
         var shortcuts = [
             {key: 'Shift-Enter', help: 'run cell'},
             {key: 'Ctrl-Enter', help: 'run cell in terminal mode'},
+	    {key: 'Ctrl-Shift-L', help: 'toggle line numbering'},
             {key: 'Ctrl-m d', help: 'delete cell'},
             {key: 'Ctrl-m a', help: 'insert cell above'},
             {key: 'Ctrl-m b', help: 'insert cell below'},