Introduction. Cardiopulmonary resuscitation (CPR) plays a key role in the event of sudden cardiac arrest. Early recognition of arrest and rapid and timely cardiopulmonary resuscitation significantly affect the outcome of a person who has experienced sudden cardiac arrest, especially in an outpatient setting. This thesis analyzes the influence of lay resuscitation on the outcome of resuscitation, especially on the survival rate of victims in whom lay resuscitation was carried out, unlike those in whom it was not the case. Research objectives. The aim of this thesis was to investigate the influence of lay resuscitation on the outcome of resuscitation itself, to analyze the results of cardiopulmonary resuscitation with regard to the establishment of spontaneous circulation, to check the availability of automatic external defibrillators and the availability of courses on basic life support measures for lay people. Research methods. For the purposes of this research work, the data of the Utstein form for the implementation of resuscitation in Varaždin County in the period from 2022 to 2023 were used. All statistical analyses were performed using MedCalc 20.305 (MedCalc Software Ltd, Ostend, Belgium). P values of less than 0.05 were considered statistically significant. Results. In the research, we used 442 Utstein forms, i.e. 442 resuscitations, of which 144 were women (33%) and 285 men (65%), and the data are unknown for 13 patients.. The most arrests were of a medical cause (365 subjects, 82.5%), while other causes were significantly less. There was no statistically significant difference in the causes of arrest between males from females, P=0.261. Lay resuscitation was performed in 219 (50%) cases. Lay people's use of AVD was used in 5 (2%) cases. Until arriving at the hospital, ROSC had a total of 49 (11%) patients, and the establishment of ROSC was associated with the initial rhythm, P<0.001 and more significantly more common in resuscitations in which lay resuscitation was originally present, P<0.001. Also, the establishment of ROSC was more frequent in cases with shorter call times until the arrival of HMS, P<0.001 Conclusion. The conclusions of this thesis highlight the importance of lay resuscitation as one of the most important factors in the chain of survival of people who have experienced sudden cardiac arrest. Education of lay people on cardiopulmonary resuscitation, on the function and purpose of automatic external defibrillators and constant raising of lay people's awareness of the importance of rapid and adequate response in case of sudden cardiac arrest are key to positive outcomes of cardiopulmonary resuscitation