Participants were purposefully recruited through mental health center and therapist referrals and through newspaper advertisements in a large midwestern city. Tobit analysis was used to identify significant predictors of domestic assault. Results revealed that 34 of the pairs were identified as violent, and 68 were identified as nonviolent according to scores on the Conflict/Tactics Scale. Results also revealed that when examined separately, each conceptual domain was significantly related to the domestic assault. However, in the full model, only the biological and social domains were statistically significant. Significant independent variables included alcohol, family income, and relationship quality; levels testosterone approached significance an independent variable. Findings provide some support for a biopsychosocial approach to the understanding of domestic violence and indicate that the best estimates of violence probability are the social variables. Tables and 90 references (Author abstract modified)