Tacrolimus and pimecrolimus represent a new class of topical nonsteroidal medications currently used in the treatment of a variety of inflammatory skin lesions. We report the case of a patient in whom topical tacrolimus therapy resulted in widespread lesions of tinea incognito. This case shows that partial treatment of dermatophytosis with griseofulvin may obscure the diagnosis. It also suggests that topical tacrolimus appears capable of inducing widespread dermatophytosis. The clinical appearance in this case was similar to tinea incognito induced by a topical corticosteroid.