Osteopetrosis is a rare sclerosing inherited dysplasia of bone caused by the deficient function of osteoclasts. At first the disease was divided into the severe infantile recessive and the more benign autosomal dominant types, but clinical differences and progress in genetic understanding have now enabled identification of two distinct autosomal dominant types. The eponym Albers-Schönberg disease should not be used as a generic term for the disease, because the single case reported almost 100 years ago almost certainly had an autosomal dominant inheritance. The diagnosis remains radiographic, supported by computed tomography (CT), if necessary. The use of magnetic resonance imaging (MRI) tends to be limited to imaging of the marrow in the severe recessive disease, which is usually fatal without marrow transplantation.