One hundred and five strains of yeasts isolated from milk of different animal origin and from typical Apulian cheeses were studied to identify and characterize yeast strains for further selection as starter cultures for cheese production. The most prevalent isolates belonged to the species Trichosporon cutaneum (15.24%), Candida catenulata (10.48%) and Yarrowia lipolytica (8.57%). In order to evaluate the potential use as starter cultures, the occurrence of some selected properties, such as fermentation of glucose and lactose, assimilation of lactic acid, citric acid and lactose, growth at 4 degrees C and production of lipolytic and proteolytic enzymes in the strains belonging to the most frequent species was tested. C. catenulata and C. zeylanoides were positive for assimilation of lactic and citric acids and showed psychrotrophic aptitude. T. cutaneum was positive for all properties tested except for glucose and lactose fermentations. Y. lipolytica was endowed with remarkable lipolytic activity also at 4 degrees C and was positive for assimilation of lactic and citric acids, growth at 4 degrees C and proteolytic activity.