The case of angiokeratoma corporis diffusum here described is believed to be the fifth reported in this country. The patient, a Caucasoid man, was admitted to the hospital at the age of 23 years, with a neurological finding of left hemianesthesia. The dermatological symptoms had appeared at the age of 18 months in the form of many dark red, non-blanching, verrucous papules measuring from 0.5 to 4 mm. in diameter. They became larger, darker, and more numerous during his childhood. Their angiokeratomatous nature was recognized at biopsy. The underlying pathology is a thickening of arterial walls, the muscle cells of the tunica media being enlarged. Since the cardiovascular, renal, respiratory, and nervous systems all become involved, the symptoms are varied. The prognosis is poor, and the cause is unknown.