The present report describes a case of cutaneous protothecosis, as confirmed by skin biopsy and culture, in a 62-year-old man with an erythematous plaque lesion on his back. The disease was initially detected after return from a trip to Taiwan. The characteristic sporangia and biochemical sugar assimilation tests indicated the organism to be Prototheca wickerhamii. Oral administration of (5-FC) failed to have any effect and so finally, the lesion had to be removed by surgical excision.