It is well established that HIV-positive persons who use stimulants such as methamphetamine are at increased risk for transmitting medication-resistant strains HIV. Mental health co-morbidities such as symptoms of post-traumatic stress disorder and HIV-specific traumatic stress may substantially contribute to increased stimulant use among HIV-positive persons. Consequently, adjuvant mental health interventions designed to address traumatic stress could ultimately improve substance abuse treatment outcomes and reduce transmission risk behavior among HIV-positive methamphetamine-using men. In particular, expressive writing is a self-administered, exposure-based intervention to address trauma that could be easily disseminated to substance abuse treatment programs without placing significant additional burden on staff for training or intervention delivery. Over the past 20 years, numerous randomized controlled trials (RCTs) have examined the efficacy of self-administered expressive writing interventions where participants are asked write about traumatic events for 15-30 minutesover 1-5 days. Findings from meta-analyses observed that expressive writing interventions improve psychological adjustment, physiological functioning, and self-reported physical health in various populations. However, to our knowledge no published research has examined the efficacy of expressive writing with active drug users. The proposed formative clinical research will examine the safety, feasibility, and potential clinical utility of delivering a self-administered, expressive writing intervention to HIV-positive methamphetamine-using men. In order to evaluate expressive writing, we will conduct a pilot RCT with 90 HIV-positive methamphetamine-using men. In addition to providing data on safety and feasibility, this RCT will provide an opportunity to examine the potential clinical utility of expressive writing with respect to measures of psychological adjustment (primary outcome) as well as substance use and HIV transmission risk behavior (secondary outcomes). Establishing that expressive writing is safe, feasible, and potentially efficacious with this population represents a crucial first step to inform a planned clinical research program. Subsequent clinical research will examine whether expressive writing can serve as an efficacious adjuvant to substance abuse treatment with HIV-positive methamphetamine-using men. Improving the effectiveness of substance abuse treatment for HIV-positive methamphetamine-using men would alleviate human suffering and could ultimately reduce HIV transmission rates.