Planning of order picking is essential process in every warehouse. In this thesis, we developed a simple warehouse simulator, which allows us to do various searches on path finding for a certain amount of items for one or more robots, using the A* algorithm. Heuristic guidance of search is mainly based on heuristic evaluation. We have implemented five different heuristic estimates, which we tested experimentally on examples with different warehouse configurations and with different numbers of robots. We also analysed the results and pointed out the drawbacks of each heuristic.