Osteoporosis is one of the comorbidities that complicating hemophilia. Recurrent hemarthrosis, chronic arthropathy and immobilization all are factors that make patients with hemophilia prone to this complication. Till recently the major emphasis of the osteoporosis diagnosis is the dual-energy X-ray absorptiometry (DEXA) scan, however, the definition of osteoporosis in pediatrics not only low bone mineral density measured by DEXA scan but also required the presence of clinically significant fracture history. Investigation target is evaluating the osteoporosis prevalence between cases with hemophilia, assessing the risk factors increasing its incidence including diet habits, the severity of hemophilia, duration between the first diagnosis of the disease and enrollment in the study and chronic hepatitis C infection. Also, considering the role of vitamin D deficiency, and another potential indirect mechanism mediated through Receptor activator of NF-Kappa-B, the Receptor activator of NF-Kappa-B ligand (RANK-RANKL) pathway has been suggested in the pathogenesis of bone disease and osteoclastic activity but remains controversial.Thirty-nine hemophilia pediatric patients were recruited from hematology clinic, Cairo university hospital, history taking, and examination were done focusing on the musculoskeletal system and dietetic data. Twenty normal age-matching children enrolled as a control group. DEXA scan results showed normal bone mineral density in 28 patients (71.8%) and osteoporosis in 11 patients (28.2%). The median Z score of patients was -1.40 (-2.2 – -0.6). There was a statistically significant decrease of bone mineral density in patients with hemophilia comparing with a control group with P-value <0.001, also we observed significantly higher serum RANKL in the group of patients with low bone mineral density ensuring the relation between RANKL and osteoclastic activity.