Objectives Although violent behaviour and psychopathology often co-occur, there has been little research on psychiatric disorders among men in treatment for intimate partner violence (IPV). This study aimed to examine the prevalence of a broad spectrum of psychiatric disorders among men voluntarily attending treatment for IPV. Setting 5 clinics for IPV treatment, located in the east, south and west of Norway, participated in the study. In a cross-sectional design, men attending therapy for violence against a partner went through a face-to-face structured diagnostic interview, the Mini International Neuropsychiatric Interview. Participants 222 men contacted the clinic during the inclusion period; 12 men did not attend and 13 men were referred to outpatient clinics. Of the 197 men who were offered therapy, 13 did not provide consent to participate in the study, 2 were excluded and 3 men missed the interview. Results A total of 179 men participated in the study. The majority were ethnic Norwegians (88%). A total of 70.9% of the men fulfilled the diagnostic criteria for at least one ongoing psychiatric disorder. Three categories of disorders stood out with approximately equal prevalences: depressive disorders (40.6%), anxiety disorders (38.5%) including post-traumatic stress disorder (18.4%) and alcohol/substance abuse (40.2%). Antisocial personality disorder was present in approximately 2/10 participants. Comorbidity was high, with nearly half of the men (48.0%) assigned two or more diagnoses. Conclusions Men voluntarily admitted to treatment for IPV harbour a wide spectrum of psychiatric disorders. Our findings suggest a need for screening procedures for psychiatric disorders as well as adoption of treatment interventions according to different types of psychopathologies and therapeutic needs. Limitations include caution in terms of generalisation to other populations not voluntarily admitted to treatment for IPV, and risk of ignoring symptoms not covered by a clinical structured interview.