Globalisation has resulted in an increase in the ethnic and cultural diversity of mental health service users. In recent years mental health policy, research and services have placed great emphasis on cultural competency training as a means of reducing disparities in mental health care. Evidence from studies measuring the effect of cultural competency training on knowledge and skills show significant positive changes post-training. However, there has been a call for further research to examine whether these improvements are sustainable. The study assessed whether there was any change in mental health professionals' self-assessment of knowledge and skills pre, post and at 3 months following training in Race Equality and Cultural Capability (RECC). A longitudinal study design was employed to evaluate the effectiveness of the training programme. Fifty-one mental health professionals completed the pre- and post-training questionnaires and 22 completed the questionnaire at 3-month follow-up. The results of the study show that, the training resulted in a significant improvement in knowledge and skills immediately post-training, which is in keeping with the findings of previous studies. However, longitudinal exploration of these changes revealed that gains in knowledge and skills were not sustained over time.