Objective: Examine trends in nonmedical use of prescription stimulants (NPS), including motives, routes of administration, sources, cost, and risk factors. Participants: 1,253 college students. Methods: Data were collected annually during academic years 2004-2005 through 2008-2009. Generalized estimating equations analyses evaluated longitudinal trends. Logistic regression models evaluated stability of associations between risk factors and NPS over time. Results: Almost two-thirds (61.8%wt) were offered prescription stimulants for nonmedical use by Year 4, and 31.0%wt used. Studying was the predominant motive (73.8% to 91.5% annually), intranasal administration was modest (less than 17% annually), and the most common source was a friend with a prescription ([greater than or equal to] 73.9% annually). Significant changes over time included decreasing curiosity motives, increasing overuse of one's own prescription, and increasing proportion paying $5+ per pill. Lower grade point average and alcohol/cannabis use disorders were consistently associated with NPS, holding constant other factors. Conclusions: Prevention opportunities exist for parents, physicians, and college administrators to reduce NPS. (Contains 3 tables.)