BACKGROUND: Nonmedical use of prescription psychostimulants such as methylphenidate and amphetamine salts for the purpose of cognitive enhancement is a growing trend, particularly in educational environments. To our knowledge, no recent studies have evaluated the use of these psychostimulants in a medical academic setting. OBJECTIVE: To conduct an online census of psychostimulant use among medical students. DESIGN: In 2011, we conducted a multi-institutional census using a 31-48 item online survey regarding use of prescription psychostimulants. PARTICIPANTS: 2,732 actively enrolled medical students at four private and public medical schools in the greater Chicago area. MAIN MEASURES: Prevalence and correlates of psychostimulant use KEY RESULTS: 1,115 (41 %) of students responded to the web-based questionnaire (range 26-47 % among schools). On average, students were 25.1 years of age (SD = 2.7, range 20-49), and single (70 %). Overall, 18 % (198/1,115) of this medical student sample had used prescription psychostimulants at least once in their lifetime, with first use most often in college. Of these, 11 % (117/1,115) of students reported use during medical school (range 7-16 % among schools). Psychostimulant use was significantly correlated with use of barbiturates, ecstasy, and tranquilizers (Pearson's correlation r > 0.5, Student's t-test p < 0.01); male gender (21 % male versus 15 % female, Chi squared p = 0.007); and training at a medical school which by student self-report determined class rank (68 % versus 51 %, Chi-squared p = 0.018). Non-users were more likely to be first year students (Chi-squared p = 0.048) or to have grown up outside of the United States (Chi-squared p = 0.013). CONCLUSIONS: Use of psychostimulants, including use without a prescription, is common among medical students. Further study of the side effects, medical implications, and use during post-graduate medical training and medical practice is needed to inform evidence-based policy.