ABSTRACT: AIM: The increased rate of psychosis and poorer service-related outcomes in UK African-Caribbeans may in part be related to racism; racism as an aetiological factor remains comparatively under-investigated. We wanted to develop a measure of perceived racism in UK African-Caribbean patients with psychosis METHODS: We modified the Perceived Racism Scale (PRS) by substituting a mental-health-services' racism domain for the employment-racism domain and administered it to a sample of 150 individuals. RESULTS: 110 people completed the PRS with a total mean perceived racism score of 54.2 for the previous year and 71.3 for the lifetime. The modified instrument had good internal consistency, and both a similar factor-analytic structure and sampling adequacy to the original instrument. CLINICAL IMPLICATIONS: The modified PRS was acceptable to the sample, withstands statistical scrutiny and produced similar totals to those in previously-tested populations. Subjective measurement of perceived racism may improve understanding of psychosis in African-Caribbeans, improve engagement and, hopefully, outcome.