Population-based surveys estimate that the prevalence of methamphetamine use is 20 times higher among men who have sex with men (MSM) compared to the general population. Methamphetamine-associated sexual risk behavior is also a driving force in the MSM HIV epidemic: methamphetamine use has been associated with increased number of sexual partners, unprotected sex acts, sexually transmitted infections (STIs), and HIV acquisition. Despite these alarming data, relatively few interventions have been tested among methamphetamine-using MSM. Among heterosexual non-injection drug users, methamphetamine use has been associated with well characterized risks for HIV and STDs including increased numbers of sexual partners, less condom use than non-methamphetamine users, engaging in sex work, and self-reported history of STDs. In parallel with the continued testing of behavioral approaches, we believe the time has come to test the feasibility and acceptability of pharmacologic interventions to reduce methamphetamine use among high-risk individuals. Pharmacologic approaches to treating substance use have been successful in treating nicotine, alcohol, and heroin dependencies. Preliminary dosing studies demonstrate that aripiprazole (Abilify), an FDA-approved, well-tolerated antipsychotic and partial dopamine agonist, reduced the effects of methamphetamine in humans and exhibited a good safety profile. We propose to expand upon these promising results by conducting a randomized, double-blind, placebo-controlled pilot study of aripiprazole among sexually-active, methamphetamine-dependent individuals.