PURPOSE: Long-term steroid therapy for various glomerular disorders in children has been known to decrease serum Vit D3 level and develop osteomalacia. The aim of this study was to observe the effect of long-term steroid therapy on growth and bone density in children with nephrotic syndrome. METHODS: Bone density of 17 steroid-treated nephrotic syndrome was compared with that of 17 similar aged healthy children by biochemical measurement, bone age and bone mineral density. Serum Vit D3, calcium, phosphorus and alkaline phosphatase were measured and bone mineral content was measured in the lumbar vertebra by dual energy X-ray absorptiometry (HOLOGIC QDR 2000 X-Ray Bone densitometer). RESULTS: There was no significant difference in height ,weight and bone age between the two groups. The mean bone density was significantly lower in children receiving steroid (0.58 +/- 0.04g/cm2) than in the control group (0.65 +/- 0.07g/cm2) (P<0.001). There was no significant correlation between duration of steroid therapy and decrement of bone density. Serum Vit D3 level was significantly lower in the group receiving steroid (16.7 +/- 6.1pg/ml) than in the control group (31.0 +/- 5.8pg/ml) (P<0.001). CONCLUSION: we conclude that alternate-day steroid therapy doesn't affect growth but may lead to decrement of serum Vit D3 level and bone mineral density in children with nephrotic syndrome.