In the elderly population, studies show the prevalence of use of prescription and consumption of medications without prescription from a licensed health care professional (self-medication), which leads to the potential for interactions with prescription drugs, adverse reactions and drug interaction. The present study aimed to identify the prevalence of self-medication, the determining factors in this practice, and the main drugs consumed without prescription in the elderly people. This paper describes cross-sectional study that evaluated self-medication practiced by elderly, who were assisted at the Strategy Health Family of São Luís/MA. Of the 100 elderly studied 63% was female and was 37% male; 72% reported using at least one medication during the days preceding the survey. Of these 33% reported exclusive use of prescribed drugs and 67% reported simultaneous use of prescribed and not prescribed. The most used non-prescribed drugs were analgesics (46,15%) and anti-inflammatory (22,31%). The most cited reasons for the practice of self-medication were general pain (65.26%) followed by fever (16,26%) and flu (7.37%). Pharmaceutical assistance should be provided as a priority to the elderly, to avoid the misuse of medicines and ensure access to the correct drugs.