Leptin is a small peptide hormone that is mainly but not exclusively, Produced in adipose tissue. Leptin plays an important role in regulating appetite and energy expenditure and also functions in the neuroendocrine, hematopoietic, and immune systems, among others. Leptin may be involved in modulating bone mineralization. The relationship between leptin and bone mineral density and bone biochemical parameters in not clear. This study examined the relationship between some bone bio chemical parameters (such as Alkaline phosphatase, phosphorus, parathyroid hormone and calcium) and serum leptin level in renal transplant recipients. we studied 72 renal transplant recipients (47 men and 25 women; age 13 to 61 years, 11 diabetic and 61 non-diabetic, mean body mass index 24.2±3.9) observed on shahrekord’s Hajar hospital. Serum calcium, phosphorus and alkaline phosphatase and also intact serum PTH and serum leptin were measured too. In this study a significant difference of serum leptin between males and females with more values in female was seen. In all patients a significant positive correlation of serum leptin level with serum iPTH was found. There was no relationship between serum leptin level with alkaline phosphotas, phosphorus, calcium, BMI, age and creatinine clearance. A negative relationship was found between serum leptin and duration of posttransplant followup. These data suggest that serum leptin affects bone metabolism in renal transplant recipients.