Mobile applications in the present day are nothing special anymore, they are used daily practically at every step. While this is already established in most of the European countries, we still don’t have an application for booking a seat on the train. Therefore, our goal was to develop an application for a mobile operating system which will enable this. This thesis covers the technologies and tools that were used in the making of our Android mobile application. The process of mobile application development is also described, including other components such as server, database and web services. At the end of our thesis we cover the test phase and conclusions.