Acroosteolysis is characterized by bone resorption in the fingers and toes and can occur in several diseases. Phalangeal acroosteolysis is a rare idiopathic form. We report a case in a 13-year-old girl with a 2-year history of swelling and skin ulcers of the second and third left fingers and second right finger. The fingers were abnormally short and the nails were hypertrophic. Roentgenograms disclosed terminal phalangeal resorption in the fingers and toes. Findings were normal from tests for inflammation and dysimmunity. Biopsies of the skin lesions showed fibrosis without inflammation. Neurological evaluation and electromyographic study were normal. Serological tests for syphilis were negative. Calcium and phosphate levels in blood and urine were normal. A diagnosis of idiopathic phalangeal acroosteolysis (Joseph and Shinz disease) was given. This inherited form of acroosteolysis is transmitted on an autosomal dominant or recessive basis. It affects the tips of the distal phalanges of the fingers and toes but occasionally spreads to other bones.