The present report describes a case of onychoprotothecosis caused by Prototheca wickerhamii in a nonimmunocompromized female. Dermatological examination showed yellowish discoloration of the left and right forefinger nails, showing onicolysis and hyperkeratosis. The repeated isolation of the algae Prototheca (organisms morula-like) as well as the repeated culture in media, Sabouraud agar, confirmed the diagnosis. The patient was successfully treated with tioconazol 1% topic solution. The aim of this paper was to present a rare condition.