The current study aimed to develop a measure for assessing the various motivations for sexual risk behavior (SRB) across commercial (involving the exchange of sex for money or drugs) and casual (nonregular) partners in a sample of inner-city, primarily African American drug users, and to examine the relationship of these motivations with a history of childhood trauma, as well as current symptoms of depression, posttraumatic stress disorder (PTSD), and borderline personality disorder (BPD). Exploratory factor analysis indicated a 5-factor solution for commercial partner type, and a 4-factor solution for casual partner type, including the motivations of sexual sensation-seeking, intimacy seeking, reassurance-seeking, emotional avoidance, and emotional expressivity. Emotional avoidance and emotional expressivity were strongly related to childhood trauma and PTSD and BPD symptoms. These results provide initial results for mechanisms underlying the relationship between SRB and a history of trauma and psychopathology. (Contains 8 tables.)