The prevalence of Type 2 (non-insulin-dependent) diabetes among offspring of conjugal Type 2 diabetic parents in India was determined by performing oral glucose tolerance tests. Diabetes was present in 50% of offspring, and 12% had impaired glucose tolerance according to the National Diabetes Data Group criteria. Thus, 62% of all offspring had abnormal glucose tolerance tests. This is the highest prevalence rate for diabetes among offspring of conjugal diabetic parents and might represent an ethnic variation of the genetic factors operating in Indian patients with Type 2 (non-insulin-dependent) diabetes.