diff --git a/lib/ace/commands/default_commands.js b/lib/ace/commands/default_commands.js
index 88621eaf..e2acb202 100644
--- a/lib/ace/commands/default_commands.js
+++ b/lib/ace/commands/default_commands.js
@@ -332,6 +332,11 @@ exports.commands = [{
     bindKey: bindKey("Ctrl-/", "Command-/"),
     exec: function(editor) { editor.toggleCommentLines(); },
     multiSelectAction: "forEachLine"
+}, {
+    name: "toggleBlockComment",
+    bindKey: bindKey("Ctrl-Shift-/", "Command-Shift-/"),
+    exec: function(editor) { editor.toggleBlockComment(); },
+    multiSelectAction: "forEach"
 }, {
     name: "modifyNumberUp",
     bindKey: bindKey("Ctrl-Shift-Up", "Alt-Shift-Up"),
diff --git a/lib/ace/editor.js b/lib/ace/editor.js
index 0abcecbf..9f22604c 100644
--- a/lib/ace/editor.js
+++ b/lib/ace/editor.js
@@ -1263,7 +1263,6 @@ var Editor = function(renderer, session) {
     };
 
     /**
-     *
      * Given the currently selected range, this function either comments all the lines, or uncomments all of them.
      **/
     this.toggleCommentLines = function() {
@@ -1272,6 +1271,13 @@ var Editor = function(renderer, session) {
         this.session.getMode().toggleCommentLines(state, this.session, rows.first, rows.last);
     };
 
+    this.toggleBlockComment = function() {
+        var cursor = this.getCursorPosition();
+        var state = this.session.getState(cursor.row);
+        var range = this.getSelectionRange();
+        this.session.getMode().toggleBlockComment(state, this.session, range, cursor);
+    };
+
     /**
      * Works like [[EditSession.getTokenAt]], except it returns a number.
      * @returns {Number}
@@ -1440,7 +1446,6 @@ var Editor = function(renderer, session) {
         });
     };
 
-
     /**
      * Executes a specific function, which can be anything that manipulates selected lines, such as copying them, duplicating them, or shifting them.
      * @param {Function} mover A method to call on each selected row
diff --git a/lib/ace/mode/text.js b/lib/ace/mode/text.js
index c0df790a..6e79baf0 100644
--- a/lib/ace/mode/text.js
+++ b/lib/ace/mode/text.js
@@ -36,6 +36,8 @@ var TextHighlightRules = require("./text_highlight_rules").TextHighlightRules;
 var Behaviour = require("./behaviour").Behaviour;
 var unicode = require("../unicode");
 var lang = require("../lib/lang");
+var TokenIterator = require("../token_iterator").TokenIterator;
+var Range = require("../range").Range;
 
 var Mode = function() {
     this.$tokenizer = new Tokenizer(new TextHighlightRules().getRules());
@@ -62,6 +64,8 @@ var Mode = function() {
         return this.$tokenizer;
     };
 
+    this.lineCommentStart = "";
+    this.blockComment = "";
     this.toggleCommentLines = function(state, session, startRow, endRow) {
         var doc = session.doc;
         var regexpStart, lineCommentStart;
@@ -84,12 +88,12 @@ var Mode = function() {
             if (ignoreBlankLines || /\S/.test(line))
                 doc.insertInLine({row: i, column: minSpace}, lineCommentStart);
         }
-        
+
         function iter(fun) {
             for (var i = startRow; i <= endRow; i++)
                 fun(doc.getLine(i), i);
         }
-        
+
         var ignoreBlankLines = false;
         var shouldRemove = true;
         var minSpace = Infinity;
@@ -112,6 +116,66 @@ var Mode = function() {
         iter(shouldRemove ? uncomment : comment);
     };
 
+    this.toggleBlockComment = function(state, session, range, cursor) {
+        var comment = this.blockComment;
+        if (!comment)
+            return;
+        if (!comment.start && comment[0])
+            comment = comment[0];
+
+        var iterator = new TokenIterator(session, cursor.row, cursor.column);
+        var token = iterator.getCurrentToken();
+
+        var sel = session.selection;
+        var initialRange = session.selection.toOrientedRange();
+        var startRow, colDiff;
+
+        if (token && /comment/.test(token.type)) {
+            var startRange, endRange;
+            while (token && /comment/.test(token.type)) {
+                var i = token.value.indexOf(comment.start);
+                if (i != -1) {
+                    var row = iterator.getCurrentTokenRow();
+                    var column = iterator.getCurrentTokenColumn() + i;
+                    startRange = new Range(row, column, row, column + comment.start.length);
+                    break
+                }
+                token = iterator.stepBackward();
+            };
+
+            var iterator = new TokenIterator(session, cursor.row, cursor.column);
+            var token = iterator.getCurrentToken();
+            while (token && /comment/.test(token.type)) {
+                var i = token.value.indexOf(comment.end);
+                if (i != -1) {
+                    var row = iterator.getCurrentTokenRow();
+                    var column = iterator.getCurrentTokenColumn() + i;
+                    endRange = new Range(row, column, row, column + comment.end.length);
+                    break;
+                }
+                token = iterator.stepForward();
+            }
+            if (endRange)
+                session.remove(endRange);
+            if (startRange) {
+                session.remove(startRange);
+                startRow = startRange.start.row;
+                colDiff = -comment.start.length
+            }
+        } else {
+            colDiff = comment.start.length
+            startRow = range.start.row;
+            session.insert(range.end, comment.end);
+            session.insert(range.start, comment.start);
+        }
+        // todo: selection should have ended up in the right place automatically!
+        if (initialRange.start.row == startRow)
+            initialRange.start.column += colDiff;
+        if (initialRange.end.row == startRow)
+            initialRange.end.column += colDiff;
+        session.selection.fromOrientedRange(initialRange);
+    };
+
     this.getNextLineIndent = function(state, line, tab) {
         return this.$getIndent(line);
     };