I was presented with this error whilst developing with Xamarin Forms For me it was simply down to copy and paste :-O. I'd created a new Xaml Page, which fully qualified was MyNameSpace.MyPage. I then copied in some Xaml which had a different name in the Xaml x:Class attribute (x:Class="NotMyNameSpace.OrPage"). I then tried to compile with our fixing the x:Class attribute and got the 'InitializeComponent does not exist' error. Once I changed the Xaml to match my actual classname (x:Class="MyNameSpace.MyPage") I was back on track and the error went away. Hope this helps. For more information have a look at forums.xamarin.com The other reason is that you may have created a Shared Xamarin Forms Project rather than a Xamarin Forms Portable project. From Craig Dunn at Xamarin (taken from Xamarin Forms Forum ) You cannot use Xaml with the Shared Project template with iOS apps (in Xamarin Studio). It's a weird combination to rem