Metabolic effects of deflazacort vs. methylprednisone were studied in prepubertal patients after kidney transplantation. Thirty-one patients participated: 15 received deflazacort and 16 remained on methylprednisone. The study started at a mean of 2.1 years after transplantation, when patients were randomized to either continue with methylprednisone or switch to deflazacort. Height velocity increased more in the deflazacort than in the methylprednisone group only during the first 2 years: 5.4 +/- 0.5 vs. 3.5 +/- 0.3 cm/year, and 4.2 +/- 0.8 vs. 2.2 +/- 0.4 cm/year p=0.007, [by two-way analysis of variance (ANOVA)]. After 2 and 3 years, the number of patients who were overweight increased in the methylprednisone group and decreased in the deflazacort group; p<0.01. Lean body mass increased more in the deflazacort than in the methylprednisone group (p=0.003). Fat body mass increased only in the methylprednisone group (p<0.01). Total cholesterol and low-density-lipoprotein (LDL) cholesterol increased in the methylprednisone group (p<0.05 and p<0.01, respectively). Total and LDL cholesterol were reduced (p<0.01 and p<0.001, respectively), whereas high-density-lipoprotein (HDL) cholesterol increased (p<0.001) during deflazacort therapy. Lumbar spine bone mineral density (BMD) decreased in both groups, but total skeleton BMD decreased only in the methylprednisone group (p<0.001). Finally, normal glucose/insulin ratio, defined as > 7, was associated (p<0.05) with the deflazacort group. Our data suggest that deflazacort therapy might improve linear growth and lean body mass and prevent excessive bone loss and fat accumulation. It also leads to an improvement in lipoprotein profile without reduction in insulin sensitivity.