Loss of BMD occurs post renal transplantation with its highest rates in the 1st six months. This work aimed to study BMD post renal transplantation, factors affecting bone post transplantation and to study the effect of treatment with vitamin D and calcium on bone loss post renal transplantation. Included patients were 30 CRF patients. Immediately pre transplantation; patients were subjected to measurement of serum creatinine, BUN, total calcium, phosphorus, total alkaline phosphatase and intact PTH. Measurement of Plasma osteocalcin as a marker of bone formation and deoxypyridinoline cross-links (DPD) in urine as a marker of bone resorption were done. BMD was studied in lumbar spine (L1-L4), distal forearm (distal 33% of radius) and hip (neck of femur) as representatives of BMD in these three sites using DEXA. Patients were classified into two groups; Group I patients: No treatment group which consisted of 15 patients. Group II patients: Included 15 patients who received oral vitamin D therapy in the form of 1-α-OH-D3; 1µg two times/week and oral calcium carbonate in a dose of 500 mg / d for the next 6 months following transplantation. Six months after renal transplantation; all patients were subjected to same investigations in addition to measurement of serum aluminum. Bone loss was found after 6 months of transplantation in both groups affecting all skeletal sites. Females were more affected than males. This bone loss could be decreased in areas of trabecular bones by the use of oral vitamin D in our given form and dosage. Incomplete resolution of hyperparathyroidism was found. Vitamin D treatment had a possible effect on hyperparathyroidism post renal transplantation. Bone resorption was found to be increased post renal transplantation.