Cutaneous protothecosis is an uncommon algal infection with a varied clinical presentation that occurs mainly in immunocompromised patients. We describe a 33-year-old Hispanic woman with AIDS who had a verrucous plaque on the dorsum of her hand. A biopsy specimen revealed organisms suggestive of Prototheca. Culture confirmed the organism to be Prototheca wickerhamii. To our knowledge, this is the first case of cutaneous protothecosis reported in a patient with AIDS.