OBJECTIVES: To explore the illicit use of specific prescription stimulants among college students and add to our understanding of reasons (motives) and routes of administration associated with illicit use of these drugs. METHODS: A random sample of 4580 college students self-administered a Web-based survey. The survey contained a variety of items pertaining to the illicit use of prescription stimulants. An extensive list of prescription stimulants was provided, and students were asked to select all the specific prescription stimulants that they had used illicitly. Items were also included to assess the motives and routes of administration associated with illicit use of prescription stimulants. RESULTS: Lifetime and past-year prevalence rates for illicit use of prescription stimulants were 8.3% (382 students) and 5.9% (269 students), respectively. Approximately three fourths (75.8%) of the 269 past-year illicit users of prescription stimulants reported using an amphetamine-dextroamphetamine combination agent (e.g., Adderall) in the past year, and approximately one fourth (24.5%) reported using methylphenidate (e.g., Ritalin, Concerta, Metadate, Methylin). Past-year illicit use of prescription stimulants was more than 3 times more likely among Caucasians (odds ratio [OR] 3.1, 95% confidence interval [CI] 1.5-6.6) and Hispanics (OR 3.8, 95% CI 1.6-9.3) compared with African-Americans, and more than twice as likely among Caucasians (OR 2.1, 95% CI 1.3-3.4) and Hispanics (OR 2.6, 95% CI 1.4-5.1) compared with Asians. The most commonly reported motives for illicit use were to help with concentration (65.2%), help study (59.8%), and increase alertness (47.5%). Other motives included getting high (31.0%) and experimentation (29.9%). Nearly every illicit user (95.3%) reported oral administration, and 38.1% reported snorting prescription stimulants. CONCLUSION: Illicit use of amphetamine-dextroamphetamine is more prevalent than illicit use of methylphenidate formulations among college students.