This master thesis presents a laboratory investigation of wave slamming forces on a vertical cylinder in deep and intermediate water. The technique of frequency focusing of the incoming wave field allows for generation of large individual waves at a particular point in the laboratory flume. This research was focused on obtaining references from the precise laboratory experiments, getting a broader insight into wave slamming phenomena and determining parameters causing it. The experimental studies revealed that there exist two types of run-up along the cylinder's lateral surface: stochastic slamming-like run-up induced by the impact of strongly breaking waves and a more organized type of run-up induced by the impact of stable and moderately breaking waves. It was also found that strongly breaking waves induce slamming loads on the cylinder in deep water and at intermediate depth. However, certain limitations for generation of strongly breaking waves at intermediate depth apply.