Vitamin D deficiency is common among children and adolescents in India, in spite of abundant sunshine. We conducted a pilot; double blind randomised controlled trial to investigate the effect of vitamin D supplementation on bone mineral content in underprivileged adolescent girls, in Pune, India. Fifty post-menarcheal girls aged 14 to 15 years were randomised to receive 300,000 IU (7.5 mg) of ergocalciferol or placebo orally, 4 times/year. All participants received 250 mg elemental calcium (calcium carbonate) daily. Outcome measures included change in serum 25-hydroxyvitamin D, size adjusted bone area and bone mineral content at total body and lumbar spine. Post supplementation, the median serum concentration of 25-hydroxyvitamin D was 75.2 (64.2-85.5) nmol/L in the intervention group and 28.1 (16.7-34.0) nmol/L in the placebo group. Increment in bone outcome measures was not different in the two groups. However, there was a positive effect of intervention in the size adjusted total body bone area (p<0.05), total body bone mineral content (p<0.05) and lumbar spine bone mineral content (p<0.05), and positive trend in lumbar spine bone area (p=0.07) in girls who were within 2 years of menarche. We conclude that vitamin D supplementation did not have a beneficial effect on skeletal mineralization in girls who were more than 2 years post menarcheal. However, there was a significant positive effect of the intervention on size adjusted total body and lumbar spine bone mineral content and a positive trend in lumbar spine bone area, in girls who were <= 2 years of menarche.