Iran is one of the largest drug consumersworldwide. Self-medication can be an important factor for this problem. The aim of the present study was to evaluate self-medication and its related factors among Department of Education staff. In this cross-sectional study, 404 subjects were randomly selected from educational organization staff in Tehran province during 2009-2010 years. The required data were collected using a questionnaire. The data were analyzed using SPSS statistical software. 81.4% of the subjects were keeping drugs at their homes. The most important reason for this was drug storage for future (64.4%). Most of the drugs that had been kept at home were analgesics (77%). Likewise, 70.5% of the subjects had self-medication. Analgesics (33.3%) were the most drugs which had been used. Furthermore, the most important factors affecting self-medication were existence of mild symptoms and independency to visit by physicians (32.9%), previous usage of drug and recurrence of similar symptoms (25.4%) and similar prescription by other physicians (22/6%). There was significant association between self-medication and profession (p=0.010), educational degree (p=0.010), number of children (p=0.001) and the maintenance of drug at home (p=0.001). Also, there was significant association between the maintenance of drug at home and educational degree (p=0.027) and income (p=0.025). This study shows that staffs of educational organization as a graduated class of people has a higher self- medication compared with other people reported by others.