Diving is a complex physical activity that requires medical fitness and physical fitness, mental maturity, special knowledge and skills, and special equipment that meets diving requirements. Recreational diving is becoming an increasingly popular sport in the whole world, and the number of certified divers in Croatia follows this trend. Therefore, in the future, more and more doctors, especially those working in emergency services, could come into contact with pathological conditions and injuries caused by an underwater environment. It is important to familiarize with their pathophysiology and clinical symptoms to be able to recognize and treat them in time, otherwise some of them can lead to fatal consequences. This paper presents an overview of the most common injuries and pathological conditions in diving and scientifically proven risks that they pose and therefore disqualifie a person from recreational diving. Drugs whose use could be a contraindication to diving with the most frequent undesirable side effects are also presented. The most common cause of diving incidents is human factor. Among the most significant we include " 3 I-s": ignorance, inexperience and indiscipline. It is therefore a necessity of professional and responsible health surveillance and systematic legislation to plan and implement appropriate practices to protect all participants in diving and minimize the risks of diving accidents.