Asians from the Indian subcontinent have received greater attention in diabetes studies because of their migration in large numbers. The prevalence of non-insulin-dependent diabetes mellitus (NIDDM) in migrant Indians is higher than that in the population residing in the Indian subcontinent and is also usually higher than in the other racial groups in the host country. However, before drawing any conclusions with reference to the high prevalence of NIDDM in the migrant Indians, careful comparisons are required with more up-to-date information available from the Indian subcontinent itself. Recent data from India indeed indicate that the prevalence rates have either been underestimated in the past or are rising. The problem is compounded by the different diagnostic criteria used for defining diabetes. Some of the possible factors which cause variations in the rates of NIDDM in this population are discussed.