Punch biopsy specimens from 4 patients with confirmed diagnosis of tinea versicolor were investigated. Hypopigmented, hyperpigmented and uninvolved sites from the same subject were compared in relation to ultrastructural alterations as a result of infection with Malassezia furfur, by light, scanning, and transmission electron microscopy. Hyperpigmented skin had thicker stratum corneum than hypopigmented but both were thicker than the uninvolved skin. A large number of tonofilaments were noticed in hyperpigmented sites in stratum granulosum. In hypopigmented skin the melanosomes were individually dispersed and fewer in number than the uninvolved skin. In hyperpigmented skin, the melanosomes were sequestered in most cells suggesting difficulty in the transfer of melanosome granules to keratinocytes. In both cases of pigmentation the most readily affected parts of the cells were cytoplasmic organelles with a latent effect on the nucleus and nucleolus. We postulate that either stage of pigmentation (hyperpigmentation or hypopigmentation) is a intermediary in nature as a result of M. furfur invasion.