<b>Study on Cross –Platform Mobile App Development With Xamarin</b> Mobile phones have started a revolution in the lives of people in the over the past few years. The ability to store, access, communicate and compute content via mobile phones has redefined connectivity and communications because of this Mobile Application Developers of this generation want their apps to be available on all the platforms. To address this issue, cross platform tool have been developed and was found to solve device functionality features, platform and device coverage problems. Choosing one single Cross platform tool for development was difficult, it was suggested that, Titanium and Xamarin were picked as a preliminary starting point. But there is android application development software where developers can develop the android application using C and .NET Framework in Xamarin Studio. Xamarin is a Cross platform mobile app development platform for building native apps on iOS, Android, and Windows apps from a common C .NET codebase. In this paper we are focusing on native application development approach and cross platform application development approach. Developing mobile applications inside Visual Studio provides a number of benefits such as Creating cross platform projects for Android, Windows and iOS applications, Working with a familiar IDE, while taking many advantages of Xamarin. iOS bindings of all Apple’s API Although developing applications using Xamarin saves time and resources, there are some inherent disadvantages. Xamarin, Cross Platform, Visual Studio, An droid, iOS 2554-2557 Issue-4 Volume-2 Harish Nair | Vineet Yadav