diff --git a/spec/app/window-spec.coffee b/spec/app/window-spec.coffee
index 12f79248f..0ae136754 100644
--- a/spec/app/window-spec.coffee
+++ b/spec/app/window-spec.coffee
@@ -1,5 +1,6 @@
 $ = require 'jquery'
 fs = require 'fs'
+{less} = require 'less'
 
 describe "Window", ->
   projectPath = null
@@ -78,6 +79,25 @@ describe "Window", ->
       requireStylesheet('atom.css')
       expect($('head style').length).toBe lengthBefore + 1
 
+    it  "synchronously loads and parses less files at the given path and installs a style tag for it in the head", ->
+      $('head style[id*="markdown.less"]').remove()
+      lengthBefore = $('head style').length
+      requireStylesheet('markdown.less')
+      expect($('head style').length).toBe lengthBefore + 1
+
+      styleElt = $('head style[id*="markdown.less"]')
+
+      fullPath = require.resolve('markdown.less')
+      expect(styleElt.attr('id')).toBe fullPath
+
+      (new less.Parser).parse __read(fullPath), (e, tree) ->
+        throw new Error(e.message, file, e.line) if e
+        expect(styleElt.text()).toBe tree.toCSS()
+
+      # doesn't append twice
+      requireStylesheet('markdown.less')
+      expect($('head style').length).toBe lengthBefore + 1
+
   describe ".disableStyleSheet(path)", ->
     it "removes styling applied by given stylesheet path", ->
       cssPath = require.resolve(fs.join("fixtures", "css.css"))
diff --git a/src/app/window.coffee b/src/app/window.coffee
index 321a60f56..3fafdd953 100644
--- a/src/app/window.coffee
+++ b/src/app/window.coffee
@@ -1,6 +1,7 @@
 fs = require 'fs'
 $ = require 'jquery'
 ChildProcess = require 'child-process'
+{less} = require 'less'
 require 'jquery-extensions'
 require 'underscore-extensions'
 require 'space-pen-extensions'
@@ -33,7 +34,7 @@ window.setUpEnvironment = ->
   requireStylesheet 'overlay.css'
   requireStylesheet 'popover-list.css'
   requireStylesheet 'notification.css'
-  requireStylesheet 'markdown.css'
+  requireStylesheet 'markdown.less'
 
   if nativeStylesheetPath = require.resolve("#{platform}.css")
     requireStylesheet(nativeStylesheetPath)
@@ -114,8 +115,17 @@ window.stylesheetElementForId = (id) ->
   $("head style[id='#{id}']")
 
 window.requireStylesheet = (path) ->
+  console.log path
   if fullPath = require.resolve(path)
-    window.applyStylesheet(fullPath, fs.read(fullPath))
+    content = ""
+    if fs.extension(fullPath) == '.less'
+      (new less.Parser).parse __read(fullPath), (e, tree) ->
+        throw new Error(e.message, file, e.line) if e
+        content = tree.toCSS()
+    else
+      content = fs.read(fullPath)
+
+    window.applyStylesheet(fullPath, content)
   unless fullPath
     throw new Error("Could not find a file at path '#{path}'")