Leptin is a small peptide hormone that is mainly produced in adipose tissues. Leptin plays an important role in regulating appetite and energy expenditure and may be involved in modulating bone mineralization. The relationship between leptin and bone mineral density and bone biochemical parameters in not completely understood. This study was designed to examine the relationship between some biochemical parameters such as alkaline phosphatase (ALP), phosphorus (P), intact parathormone (iPTH) and calcium (Ca) with serum leptin level in renal transplant recipients. We studied 72 renal transplant patients (47 men and 25 women) with mean ages of 44 (± 12) years and mean body mass index (BMI) of 24.2 ± 3.9Kg/m² .Serum Ca, P, ALP, iPTH and serum leptin were measured. In this study a significant difference of serum leptin between males and females with higher values in females was seen. In patients a significant positive correlation of serum leptin with serum iPTH was found. There was not relationship between serum leptin with ALP, P, Ca, BMI, age and creatinine clearance. A negative relationship between serum leptin and the duration of kidney transplantation was found. Positive relationship of serum leptin with serum parathormone suggests that leptin may affect bone metabolism in renal transplant patients.