Aneurysmal bone cyst (ABC) is a benign expansible cystic lesion most often occuring during the second decade of life. It may occur in any bone in the body. The etiology and pathophysiology remain unclear. Treatment has been intralesional curettage. Spontaneous regression is not common. Other surgical options have been suggested. We describe the case of an 8-year-old asymptomatic patient with spontaneous regression of a frontal aneurysmal bone cyst in a 4-month period. In the diagnosed cases of ABC on the skull it is important to establish differential diagnosis with benign and malignant bone tumors like giant cell tumors. In order to obtain precise information on cases with spontaneous regression, serial radiological studies previous to surgery should be performed in asymptomatic patients.