Pityriasis versicolor (PV) is a widespread dermatomycosis caused by yeasts. Erythrasma is a superficial bacterial skin disease affecting the major folds of the body, particularly the groin. We report the case of a 45-year-old man, affected by PV, exclusively localized in the inguinal folds and in the inner surface of the thighs, characterized by lesions clinically reproducing erythrasma. The authors underline the possibility that PV mimics erythrasma and vice versa, especially in those countries in which both diseases are quite common, and stress the importance of performing a simple mycological examination to avoid gross diagnostic and therapeutic errors.