Background: Thalassemia is the most common cause of chronic hemolytic anemia and is correlated with significant morbidity and mortality. Osteoprotegerin (OPG) is an α tumor necrosis factor receptor superfamily glycoprotein that acts as a decoy receptor for the receptor activator of nuclear factor kappa B ligand (RANKL), exerting an antiresorptive bone effect and also play critical roles in hypogonadism associated osteoporosis. Objective: Toexplore the serum levels of RANKL and OPG in adult Egyptian females with Beta-Thalassemia Major (BTM) and to detect their relations with female hypogonadism Patients and Methods: a prospective cross-sectional controlled study enrolled 50 control females and 45 women with BTM. We measured OPG and RANKL by ELISA, Bone mineral density (BMD) of the lumbar spine and femoral neck was measured by dual-energy X-ray absorptiometry  Results: Among 45 patients with BTM, 27 patients had hypogonadotropic hypogonadism, and they had significantly higher values of serum RANKL (8.3±1.8pmol/l) compared to BTM without hypogonadism (5.9±1.01) and controls (5.5±1.11). Regarding serum OPG, there were no non-significant differences between the studied groups. Linear regression analysis test revealed that serum RANKL levels were independently correlated with BMD femur and spine, while serum OPG levels were independently correlated with BMD spine and LH. The sensitivities and the specificities of serum RANKL levels by ROC tests to discriminate against BTM patients with hypogonadism were 91.1% and 96%. Conclusions: Serum RANK levels elevated in BTM patients particularly hypogonadism groups. The diagnostic power of serum RANKL was highly significant thus, it could be used as a biological marker of hypogonadism in BTM.