Introduction: Osteopetrosis is an inherited disease that causes thickening of the cranial bone. The need for both cerebral decompression and intracranial volume-enlarging cranioplasty in the same surgical session in a patient whose intracranial pressure is elevated cannot be prevented and is a very rare decision in neurosurgery practice. It is seen in the literature that the only indication that can lead to this surgery is osteopetrosis. Case report: A 24-year-old female patient with osteopetrosis admitted with the complaint of severe headache that did not respond to medical treatment, and surgery was decided. After decompressive craniectomy was performed with difficulties, cranioplasty with titanium mesh was performed in the same session to protect the cerebral tissue, to close the defect area, and to give more space to the cerebral tissue. Conclusions: It was observed that the complaints of increased intracranial pressure were completely resolved with unilateral cranial decompression in the early postoperative period and at the end of 2 years. The surgical intervention technique performed on the patient and the radiological findings obtained during the follow-up are presented. We think that performing cranioplasty with titanium mesh, which is used to protect and save the cerebral tissue in patients with osteopetrosis, is the most appropriate choice.