The HIV disease is caused by the penetration of the human immunodeficiency virus into the bloodstream, followed by a decline in the immune system and the development of AIDS, which eventually leads to death. AIDS was diagnosed in 1981 as a new disease in the United States. Croatia is one of the countries with a low number of registered people living with HIV. HIV can be transmitted through unprotected sexual contact, through blood and from an infected mother to her child. Since the most common route of transmission is through unprotected sexual contact, HIV/AIDS is considered to be a sexually transmitted disease. Clinical symptoms can vary between patients, and the most common are fatigue, fever, headache, sore throat, swollen lymph nodes, and so on. Serological tests are performed in the HIV diagnosis to confirm the presence of antibodies. Treatment is performed with antiretroviral drugs that prevent further multiplication of the virus. It is very important to avoid risky behaviors and adhere to all protection measures to prevent the disease. Among healthcare professionals, the most common route of transmission is through blood, by pricking a contaminated needle. A survey was conducted on a part of the population on the participants' awareness of HIV/AIDS and protection measures for HIV/AIDS via an online questionnaire using Google Forms in the period from February 1 to May 1, 2021. The aim of the research was to examine the population's level of knowledge about HIV/AIDS. A total of 693 participants participated in the survey. The survey questionnaire consisted of a total of 16 questions, where the first three questions related to sociodemographic characteristics, and the rest to knowledge examination. The research was anonymous and voluntary. The study involved 554 women and 139 men, most participants were aged 18 to 30, and most of them had a university degree. The obtained results show that the participants were very informed about HIV/AIDS and HIV/AIDS protection measures, and are therefore very satisfactory, but as many as 37.2% of participants did not use protection during sexual intercourse, therefore even more effort should be invested into educating the population, especially young people, to further understand the importance of adhering to disease protection and prevention measures.