A 2017 update of the resuscitation guideline indicated the use of cardiopulmonary resuscitation (CPR) feedback devices as a resuscitation teaching method. The aim of the study was to compare the influence of two techniques of CPR teaching on the quality of resuscitation performed by medical students. The study was designed as a prospective, randomized, simulation study and involved 115 first year students of medicine. The participants underwent a basic life support (BLS) course based on the American Heart Association guidelines, with the first group (experimental group) performing chest compressions to observe, in real-time, chest compression parameters indicated by software included in the simulator, and the second group (control group) performing compressions without this possibility. After a 10-minute resuscitation, the participants had a 30-minute break and then a 2-minute cycle of CPR. One month after the training, study participants performed CPR, without the possibility of observing real-time measurements regarding quality of chest compression. One month after the training, depth of chest compressions in the experimental and control group was 50 mm (IQR 46-54) vs. 39 mm (IQR 35-42; p = 0.001), compression rate 116 CPM (IQR 102-125) vs. 124 CPM (IQR 116-134; p = 0.034), chest relaxation 86% (IQR 68-89) vs. 74% (IQR 47-80; p = 0.031) respectively. Observing real-time chest compression quality parameters during BLS training may improve the quality of chest compression one month after the training including correct hand positioning, compressions depth and rate compliance.