The purpose of this thesis is to analyze the problem of developing cross-platform applications and to demonstrate the process of development by creating a simple cross-platform desktop application with Qt framework. In the introduction, the purpose of the thesis was described in detail. In the second chapter, Qt framework, tools for cross-platform development and the details of licensing were presented. In the suceeding chapter there is a description of the application that was developed and a step-by-step process of the development with Qt Creator. In the fifth chapter the process for preparing build environments for Windows 8, OS X Mavericks and X11 (on Lubuntu GNU/Linux) platforms was described. In chapter six the application was tested on all three platforms, and in the last chapter the usability and potential improvements of the results were analyzed.