Osteopetrosis is a rare congenital disorder of bone resorption, caused by failure of osteoclasts to reabsorb immature bone. Malignant infantile osteopetrosis presents in early life with generalized osteosclerosis and decreased bone marrow spaces, resulting in anemia, splenohepatomegaly due to extramedullary hematopoiesis, cranial nerve compression, and growth failure. It is a fatal condition with death occurring within the first year of life. Bone marrow transplant remains the only curative treatment. We present a report of an infant with splenohepatomegaly, who was diagnosed with malignant infantile osteopetrosis.