Introduction: In order to become a life guard, a person has to successfully pass the required medical examination, the fitness and skills test for life guards and first aid training, which has to be renewed every three years. Purpose: The purpose of the thesis is to identify the theoretical knowledge of Posavje region life guards about first aid, and analyse, if the knowledge of life guards during their licence period differs and based on this we determined, if the education for the licence should be more frequent or whether they would need additional training during the licence period. Work methods: The descriptive work method was used to prepare the thesis. The collection of data took place with the use of a survey questionnaire, which has been physically delivered to life guards of the Posavje region. Results: 48 respondents participated in the research, the majority of them were male (94 %), the most common level of education was high school or secondary vocational education (48 %). The majority of respondents (85 %) does not have formal medical education. The majority (35 %) of the questioned life guards perform the life guard job for more than 5 years, but most of them perform this job seasonally (37 %). The survey was divided into sets. The respondents showed the best knowledge in the field of wound care (84 %), followed by emergency situations (72 %), basic life support (69 %), approach and examination of the injured (66 %), use of oxygen (62 %), immobilisation (61 %), AED use (52 %) and required equipment (42 %). The respondent averagely provided 20 out of 29 correct answers (68 %). The knowledge of life guards in the period of up to 1 year after obtaining the licence, in the period of 1-3 years after renewing the licence and of those, who did not yet renew the licence, was averagely the same (20/29 correct answers). Discussion and conclusion: In average, the respondents have passed the knowledge examination, which has been prepared based on our criteria, but as individuals, 39 out of 48 were successful and 9 of them did not pass the examination. By comparing the results of the respondents considering the time of acquiring the licence or its renewal, we found that the knowledge is not significantly different. Based on the research and comparison we conclude that the 3-year period for the licence renewal is sufficient.