There are many different methods for fitting and analysing O-C diagrams. We present a new fitting tool for analysing O-C diagrams. Our method is based on Genetic Algorithms and Markov chain Monte Carlo. Monte Carlo method is used also to a very good estimation of errors of the parameters. Unlike many others fitting routine, our method does not need any initial values of fitted parameters. Fitting using presented software is quite simple thanks to a very intuitive graphic user interface. Currently, nine most common models of periodic O-C changes are included in this software.