The present pilot study hypothesized that degree of exposure to prenatal testosterone interacts with a history of lifetime physical abuse (LPA) to predict the cognitive (anger rumination) and behavioral (intimate partner and interpersonal violence) components of aggression within incarcerated methamphetamine (MA) users. In addition, we hypothesized that the degree of exposure to prenatal testosterone interacts with LPA to predict cognitive flexibility (Stroop Color-Word performance). Male inmate MA users (N = 60) completed neuropsychological and paper/pencil tests. Hand photocopies were also obtained to index prenatal testosterone exposure. Five covariate-adjusted moderation models were tested using anger rumination, intimate partner violence (IPV) perpetration, interpersonal violence perpetration (before and while incarcerated), and Stroop Color-Word T-score as the criteria, prenatal testosterone exposure as the predictor, and LPA as the moderator. Results indicated that, in individuals with a history of LPA, exposure to higher levels of prenatal testosterone exposure predicted greater anger rumination, lower Stroop Color-Word test T-scores, and lower frequencies of IPV perpetration. Findings were not significant in individuals without a history of LPA. This research suggests that biochemical and psychosocial vulnerabilities influence anger rumination and cognitive flexibility, which may render incarcerated MA users at greater risk to relapse or recidivate upon release from prison. (Am J Addict 2012;00:1–7)