Family histories of 135 Asian Indian and 146 European NIDD patients attending clinics in Ealing and Hammersmith Hospitals were obtained, using a detailed questionnaire. Forty‐five per‐cent of Asian and 36% of European patients had a first‐degree relative with diabetes. Twenty‐eight per‐cent of Asians and 20% of Europeans had one diabetic parent. In 10% of Asians and 1% of Europeans, both parents were diabetic (p<0.01). Autosomal‐dominant inheritance was seen in 14% of Asians and 4% of Europeans (p<0.01). The higher frequency of diabetes in parents, and the higher frequency of dominantly‐inherited diabetes among Asians compared to European NIDD patients, suggest that genetic mechanisms operating in NIDD are different in different ethnic groups.