A motivational interviewing (MI) approach focused on harm reduction of substance use may provide a way for therapists to better engage and retain DWI clients in the treatment process. This study involved 25 individuals who were assessed using a MI approach. Of the 25 individuals, eight met qualifications for a substance use disorder and were referred for treatment. All eight individuals completed the treatment program. The other 17 initially did not meet criteria for a substance use disorder and were not officially mandated to treatment. However, 14 of these individuals (82 per cent) came back for follow-up harm reduction sessions. Furthermore, within a 24-month follow-up period, none of the eight treated or 14 harm reduction session attendees were subsequently arrested for a DWI following discharge from the program. In contrast, one of the three individuals that chose not to participate in further harm reduction sessions was subsequently arrested for a DWI in the follow-up period. The findings suggest that an MI approach can be effective with DWI offenders.