The basidiomycetous yeast Malassezia has been linked to a number of disease states such as seborrhoeic dermatitis, dandruff and pityriasis versicolor. Much confusion has arisen as to its role in these disease states as this fungus is found inhabiting the stratum corneum of approximately 90% of the human adult population. Malassezia yeasts are lipophilic organisms, some species showing a specific requirement for long chain fatty acids for in vitro culture. The object of the experiments undertaken in this study was to elucidate the role of Malassezia yeasts in dandruff and seborrhoeic dermatitis.