Steroid-related bone loss is a recognized complication after renal transplantation. Quantitative ultrasound (QUS) of bone measures bone structure besides bone mass. We investigated the influence of corticosteroid therapy on QUS parameters in the 1st year after renal transplantation. A total of 119 renal transplant recipients were randomized to receive either a steroid-free regimen or a regimen with prednisone during 4 months. In 96 patients (steroid-free n=49, steroids n=47), dual-energy X-ray absorptiometry (DXA) parameters of the lumbar spine and the right hip, and QUS parameters of the right calcaneus were measured at baseline, 3, and 12 months after transplantation. Despite a significant difference in steroid use between the two groups, there was no statistically significant difference between the two groups in DXA and QUS parameters at any time point. BMD of the lumbar spine decreased at 3 months and recovered hereafter to the baseline value. BMD of the femoral trochanter decreased at 3 months and remained stable hereafter. The QUS parameter broadband ultrasound attenuation (BUA) was significantly lower at 12 months after transplantation compared with baseline (steroid-free -4.1+/-1.5%, steroids -2.6+/-1.5%). In contrast to the DXA parameters, BUA continued to decrease (P<0.05) between 3 and 12 months after transplantation in both groups. It is concluded, that the usage of a moderate dose of steroids during 4 months after renal transplantation had no important influence on QUS parameters of the calcaneus. While BMD remained stable or improved between 3 and 12 months after transplantation, the decrease in BUA seems to reflect a continuing change in bone structure in this population with preexistent renal osteodystrophy.