In recent years, the number of immigrant perpetrators who attend treatment programmes for partner violence has increased. In this study, the effectiveness of a psychological treatment programme for immigrant men who have committed a gender-based violent crime was evaluated. The sample was composed of 300 individuals (150 immigrants and 150 citizens) who received treatment in the batterer intervention programme developed in Pamplona (Navarra). A two-group design was used (immigrants and citizens) with multiple, repeated evaluations (pre-treatment, post-treatment, and 12-month follow-up). Results showed the usefulness of the programme, with no statistically significant differences in the success and improvement rates observed between the immigrant and citizen patient groups. Post-treatment success rate was 34.6% both in the immigrant group and the citizen group. The improvement rate was 51.3% in both groups. Results at 12-month follow up were nearly the same. The combined rate of success and improvement was 87.3% among immigrants and 86.6% among citizens. In addition, the associated psychopathologic symptoms exhibited significant improvement. The tested programme was shown to be effective in the treatment of immigrant batterers.