Earlier studies have shown that individuals whose mothers were diabetic when they were in utero, have an increased risk of early obesity, and impaired glucose tolerance (lGT) and type 2 diabetes in adult life. This study was designed to test whether adiposity, glucose tolerance and insulin concentrations are altered in Indian children born to mothers with gestational diabetes (GDM), and are related to maternal glucose and insulin concentrations in pregnancy even in the absence of GDM. 830 pregnant women attending the antenatal clinics of the Holdsworth Memorial Hospital (HMH), Mysore, India underwent an Oral Glucose Tolerance Test (OGTT) at 30+/-2 weeks. 674 of these women delivered at HMH. Detailed anthropometry was performed on the offspring at birth, and annually thereafter. 585 mothers returned with their offspring at 5 years of age for detailed investigations including OGTT for glucose and insulin concentrations, bio-impedance for fat estimation and blood pressure measurement. OGTT was administered to mothers and fasting plasma glucose and insulin concentrations were measured in fathers. The Mysore babies were small compared to UK neonates, but the deficit varied for different body measurements. While birthweight (-1.1 SD) was considerably lower, crown-heel length (-0.3 SD) and subscapular skinfold thickness (-0.2 SD) were relatively spared. At five years, subscapular skinfold thickness was larger than the UK standards (+0.23 SD, p<O.OOl) despite all other body measurements being significantly smaller. Findings at 5 years were similar in comparison with another standard, based on Dutch children. At 5 years, girls in the cohort had higher insulin concentrations and were more insulin resistant. Body fat was the strongest predictor of glucose and insulin concentrations independent of other body components and parental characteristics. Newborns of the mothers with gestational diabetes were larger in all body measurements than control neonates (born to non-GDM mothers and non-diabetic fathers). At one year, these differences had diminished and were not statistically significant. At five years, female, but not male offspring of diabetic mothers had larger subscapular and triceps skinfolds (P=O.Ol) and higher 30- and 120-minute insulin concentrations (P<0.05) than control females. Even in the control offspring maternal insulin area-under-the-curve was positively associated with 30-minute insulin concentrations, after adjusting for sex and maternal skinfolds (P<O.OOl). Offspring of diabetic fathers (n=41) were lighter at birth than controls; they showed no differences in anthropometry at five years. In conclusion, Maternal GDM is associated with adiposity and higher insulin concentrations in female offspring at 5 years. The absence of similar associations in offspring of diabetic fathers suggests a programming effect of the diabetic intra-uterine environment. With increasing levels of obesity and IGT among Indian mothers, these effects may be contributing to the rise of type 2 diabetes in India. Our continuing follow-up aims to study the long-term effects of higher maternal glucose concentrations in the absence of GDM.