The purpose of the study was to analyse the biological, environmental and personality causes leading to suicide attempts. The study included 168 patients after suicidal intoxication basing on anamnesis from subjects studied and members of their families. The intelligence quotient and electroencephalographical examination has also been performed in subjects studied. The main causes of suicidal attempts were the unproper familial and educational environment, the lack of close relations with members of family, the lack of adequate reference patterns of social roles, the lowered resistance against difficult situations and the tendency to impulsive actions in a part of subjects studied conditioned biologically. The frequent cause of suicidal attempt was in demonstration focusing the attentions of relatives on difficult problems arising from life situation.