Abstinence self-efficacy, or the confidence in ones' beliefs in one's ability to effectively engage in behaviors to maintain substance use abstinence, is a crucial recovery resource. However, little research has been conducted on what predicts increases in this recovery resource. Understanding predictors of abstinence self-efficacy could help social service practitioners in creating effective treatment plans/interventions while extending what is presently known in this small body of research. Predictors of abstinence self-efficacy were analyzed among a sample of ex-offenders (224 men and 46 women) who were completing inpatient treatment for substance use disorders. Hierarchical linear regression was conducted to examine changes in participants' abstinence selfefficacy in relation to factors directly related (HIV-risk drug use behaviors, substance use, 12-step meeting attendance) and indirectly related (HIV-risk sexual behaviors, incarceration histories) to substance use. HIV-risk sexual behaviors and substance use predicted significant decreases in abstinence self-efficacy whereas 12-step meeting attendance predicted significant increases. However, incarceration histories and HIV-risk drug use behaviors were not significant predictors of abstinence self-efficacy. Findings suggest HIV-risk sexual behavior should be considered when assessing relapse prevention for persons with substance use disorders, and that researchers should examine behaviors that are not directly related to substance use when investigating recovery resources.