Infantile malignant osteopetrosis (IMOP) is a rare bone resorptive disorder with an autosomal recessive inheritance pattern. It is characterized by increased bone density due to osteoclastic failure in differentiation or function. The clinical manifestations of IMOP start at birth or infancy with varied rings according to the type and degree of osteopetrosis. We presented a 3-year-old female patient referred to us due to chronic anaemia six months ago. The physical examination revealed hepatosplenomegaly, axial hypotonia, and visual impairment. Blood investigation revealed pancytopenia and hypocalcemia. Radiologic studies revealed a generalized increase in bone density, abnormal metaphyseal remodelling, and rain atrophy. The bone marrow aspiration (BMA) shows dry tap and hypocellularity of all cell lines. IMOP was diagnosed depending on clinical, radiologic, and BMA results. In conclusion, IMOP is relatively uncommon. Accurate diagnosis should be made through clinical, BMA, and radiologic investigations, especially in a resource-limited setting, as performed in our case.