Secondary hyperparathyroidism in dialysis patients are supposed to disappear after renal transplantation (RTx), but it often takes a long time. The aim of this study was to evaluate the duration of regression of glandular hyper function and possible role of duration of dialysis & PTH level in out come of parathyroid function after RTx. In 38 renal transplanted patients (12=females/26 males) with mean age of 38±12 years & mean duration of dialysis 30.84±20.41 months, serum concentration of intact parathyroid hormone (iPTH) & calcium, phosphate& alkaline phosphatase was measured before and 1,3,6 &12 months post successful RTx (Creatinine<1.7mg/dl). None of patients receive calcium & Vit D derivatives after RTx. The mean iPTH decreased from 238.79 ± 182.45 pre-transplantation to 100.43 ±63.71pg/ml one month post-transplantation (P<0.002) & it decreased significantly to 61.81±25.45; 48.92 ±25.44; 37.61 ± 18.52; at months 3, 6 &12 respectively (p<0.001). Before RTx 92% of patients had iPTH higher than normal & values greater than twice the upper normal limit were found at 66%. One, 3, 6 &12 months after RTx ,26; 52%; 86% & 89%; had normal iPTH level respectively. There was significant correlation between duration of RTx & duration of normalization of parathyroid function (p<0.01). Of the many variables analyzed, pre-transplant iPTH (r= 0.42; P< 0.01) & duration of dialysis (r= 0.42; P<0.001) significantly correlated post-transplant iPTH at months 1, 6 & 12 after RTx. Resolution of hyperparathyroidism after RTx needs more than 3 months in half of patients. Duration of dialysis & magnitude of pre-transplant hyperparathyroidism determine long-term post-transplant parathyroid function.