Timely first aid (FA) for acute conditions makes it possible to improve treatment outcomes and sometimes save human life. Assessing the basic knowledge about FA will help develop a rational system for training and dissemination of knowledge about FA. The study was aimed to perform quantitative and qualitative analysis of mistakes made by residents of Moscow and Moscow Region during assessment of their basic knowledge about FA. The questionnaire consisting of 10 questions (four possible answers, among then one correct) was created. Polling conducted before testing showed that all the respondents had basic knowledge about FA. The total study sample was 946 individuals (aged 15 years and older), it was divided into group based on the fact of having/not having medical education. It was found that the basic knowledge about FA was generally low, mainly due to the respondents having no medical education. Qualitative analysis of the answers revealed a large number of gross mistakes reflecting a high risk of wrong actions leading to deterioration of health of a victim or FA provider. The study confirms the fact of insufficient awareness of various categories of citizens, including healthcare professionals, on the issues of FA, which suggests the need to improve the system for training and dissemination of knowledge about FA across the population.