Abstract: The aim of the present study was to evaluate the knowledge and behavior toward antibiotic self-medication among college students in the capital of Iran (Tehran). A close and open-ended questionnaire was used to collect data from a sample of 160 students, randomly chosen from Shariaty Technical Faculty, Tehran, Iran. Data was collected using self administered questionnaires with open-ended and close-ended items. Data were entered and analyzed using SPSS 14 and the results were presented as the percentage. About 97.5% of respondents filled and returned the questionnaire. Self-medication with antibiotics was reported by 53% of students during the last 3 months. The main indication for self-medication with antibiotics was respiratory problems (73.3%) such as common cold and sore throat. Amoxicillin was the most commonly used antibiotic (40%). The main source of medicines was drugs which stored in students home (47.8%) and after that drugstores (44.8%). Only 26.8% of antibiotic users completed the course of antibiotic therapy. The prevalence of self-medication with antibiotics among college students was high. Educational programs are needed to teach university students about the potential problems of self-medication with antibiotics.