This study investigated ethnic differences in diabetes-specific knowledge, illness perceptions, self-management, and metabolic control among black-African, black-Caribbean,and white-British populations with type 2 diabetes. The study also examined associations between demographic/disease characteristics and diabetes-specific knowledge, illness perceptions, selfmanagement, and metabolic control in each of the three ethnic groups. Design: Cross-sectional Setting: Diabetes/retinal screening clinics in Hackney and Brent, London. Methods: Black-African, black-Caribbean and white-British populations with type 2 diabetes were asked to participate. Questionnaires measuring demographic/disease characteristics, diabetes-specific knowledge, self-management, and illness perceptions were used for data collection. Data for glycated hemoglobin (HbA) and microvascular complications were obtained from medical records. Ethnic differences in diabetes-related measures were estimated using analysis of variance/covariance. Multiple regression techniques were used to determine relationships between demographic/disease characteristics and measured diabetes-related outcomes. Results: Three hundred and fifty-nine patients participated in the study. White-British participants had high diabetes-specific knowledge compared to their black-African and black-Caribbean counterparts. Black-Africans reported better adherence to self-management recommendations than the other ethnic groups. Compared to the white-British patients, blackAfrican and black-Caribbean participants perceived diabetes as a benign condition that could be cured. Educational status and treatment category were determinants of diabetes-specific knowledge in all three ethnic groups. However, different demographic/disease characteristics predicted adherence to self-management recommendations in each ethnic group. Conclusion: Clearly, there is disease (diabetes) knowledge-perception variation between different ethnic groups in the UK which may partly influence overall disease outcome. It is plausible to recommend screening, identifying, and dispelling misconceptions about diabetes among ethnic minority patients by health care professionals as well as emphasizing the importance of self-management in managing chronic diseases such as diabetes.