OBJECTIVE: The aim of this study was to evaluate and compare the level of knowledge and attitudes towards the automatic external defibrillators (AED) of nurses and firefighters in Šibenik-Knin County. METHODS: The research was conducted in July 2017 in two institutions: the Department of Emergency Medicine of Šibenik-Knin County and the Public Fire Department of the city of Šibenik. A total of 83 participants participated in the study, out of which 42 nurses/technicians and 41 firefighters. Respondents filled out a questionnaire made only for the purpose of this research. The questionnaire contained sociodemographic questions, questions about education, knowledge about AED and cardiopulmonary resuscitation (CPR), and questions about attitudes towards use of AVD. RESULTS: Nurses/technicians were better educated than firefighters. They had greater knowledge overall and greater specific knowledge about AED and CPR. Only 15 (38.46%) nurses/technicians and 6 (14.63%) firefighters were able to indicate the location of the AED device at their place of residence. Generally, respondents had positive attitudes towards the AED devices, but they were more pronounced in nurses/technnicians.Using the linear regression model, only education showed statistically significant correlation with AED attitudes. CONCLUSIONS: Nurses/technicians have statistically significantly more positive attitudes towards AED, a significantly higher level of education, and greater general and specific knowledge than firefighters. Greater awareness about AVDs reflected in more positive attitudes. Low overall awareness about AVD locations found in the Šibenik-Knin County has to be overcome by introducing courses and continuing education programs.