Background. Osteopetrosis represents a lack of apoptosis in osteoclastic activity, producing a highly calcified but fragile bone due to excess of calcium. Excess calcium deposited in the medullary compartment leads to bone expansion, producing a predominant secondary hematopoiesis accompanied by significant visceromegaly and pancytopenia. Osteopetrosis is a genetic disease with a low prevalence and incidence in Mexico. Case report. We report the case of a 12-year-old female who presented with bone pain in the lower extremities at an early age. A radiological diagnosis of ostepetrosis was made, and the condition was complicated by multiple fractures and infections. The patient was treated with dietary modifications and analgesics and was considered to be a candidate for hematopoietic stem-cell transplant. Conclusions. Osteopetrosis is a rare and complex disease without any current effective medical treatment, necessitating a multidisciplinary approach. Hematopoietic stem-cell transplantation offers a promising alternative treatment for certain cases of severe osteopetrosis.