Blood levels of parathyroid hormone usually decrease after successful renal transplantation. However, some patients with good renal function develop elevated PTH levels and/or persistent hypercalcemia. The aim of this study was to determine the prevalence of hyperparathyroidism and hypercalcemia three months and one year after transplantation and to assess the correlation between medical care with prevalence of hyperparathyroidism. 121 patients with chronic renal failure, who had successful transplantation between August 2000 and August 2002 in Namazee Hospital, were evaluated. Ca, Ph, Albumin, Creatinine and iPTH were assessed before transplantation, and three months after the operation. 21 patients developed hypercalcemia and were followed for 1 year. Five cases were excluded from the study: One patient developed chronic graft ejection and four cases had immigration or poor follow ups. 3 months after operation, 9 (7.4%) subjects had PTH values above 60pg/ml and 21 (17.4%) were hypercalcemic. Five cases were excluded and at the end of the first post Op year, seven cases (43.8%) out of 16 had persistent hypercalcemia. At all, nine patients out of 121 (5.6%) were still hypercalcemic at the end of the 1st year. The maximum level of calcium was 11.7mg /dl and no patient had any indication for parathyroidectomy. Significant correlation was found between duration of dialysis and age with level of PTH after transplantation. (P<0.05) The prevalence of hypercalcemia, 1 year after transplantation in this study is approximately similar to previous reports. Meticulous medical care and management before and after transplantation decreases persistent hypercalcemia and renal osteodystrophy after transplantation.