Abstract Background A comparison of the anthropometry of children and adolescents with that of their parents at the same age may provide a more precise measure of intergenerational changes in linear growth and body mass index (BMI). Methods New Delhi Birth Cohort participants (F1), born between 1969 and 1972, were followed up for anthropometry at birth and at 6-monthly intervals until 21 years of age. At variable intervals 1447 children, aged 0–19 years (F2) and born to 818 F1 participants, were measured (weight and height), providing 2236 sets of anthropometries. Intergenerational changes (F2-F1) in height and BMI [absolute and standard deviation (SD) units] were computed by comparing children with their parents at corresponding ages. Results F2 children were taller (P < 0.001) than their parents at corresponding ages; the increase {mean [95% confidence interval (CI)] World Health Organization SD units} was 0.97 (0.83, 1.11), 1.21 (1.10, 1.32), 1.09 (0.98, 1.19), 1.10 (1.00, 1.21) and 0.75 (0.65, 0.85) for age categories of 0–5, 5–7.5, 7.5–10, 10–12.5 and >12.5 years, respectively. In absolute terms, this increase ranged from 3.5 cm (0–5-year-olds) to 7.5 cm (10–12.5-year-olds). The corresponding increases in BMI SD scores were 0.32 (0.18, 0.47), 0.60 (0.45, 0.75), 1.13 (0.99, 1.27), 1.30 (1.15, 1.45) and 1.00 (0.85, 1.15), respectively. The absolute BMI increase ranged from 1–3 kg/m2 at >5 years age to ∼3 kg/m2 at >10-years of age. The intergenerational increases were comparable in both sexes, but were greater in children born and measured later. A positive change in socioeconomic status was associated with an increase in height across the generations. Conclusions Children and adolescents, throughout the ages 0–19 years, have become considerably taller and have a higher BMI than their parents at corresponding ages in an urban middle-class Indian population undergoing socioeconomic improvements.