Abstract: A stages-of-change motivational interviewing (SOCMI) treatment approach was compared with a standard cognitive behavioral therapy gender reeducation (CBTGR) approach in a sample of 528 English-speaking and Spanish-speaking male batterers who were randomly assigned to 49 26-week groups in either condition. Blind ratings of therapist adherence differentiated the two conditions. Language spoken neither predicted outcome nor interacted with treatment. The SOCMI curriculum led to significant reductions in female partners' reports of physical aggression at follow-up, but not to changes in self-reported aggression. Men who were initially less ready to change benefited more from the SOCMI approach while men who were more ready to change benefited more from the CBTGR approach. Results suggest the importance of tailoring abuser intervention programs to individuals' initial readiness to change.