The yeast microbiota present on the surface of grapes of two Vitis vinifera varieties, Pedro Ximénez and Tempranillo de Rioja, grown in the Montilla-Moriles region of southern Spain was identified. The changes between veraison and the physiological ripeness time during 3 years were monitored. Overall, the yeast microbiota isolated was of oxidative metabolism. Sporobolomyces roseus and Cryptococcus albidus species occurred at all physiological stages, in the two Vitis vinifera varieties, and the three seasons studied. On the other hand, Kloeckera apiculata was never detected and Saccharomyces cerevisiae was scarcely isolated, it was only present, testimonial, in Tempranillo de Rioja grapes during the 1992 vintage. The widest variety of yeast species was observed in the 1992 season, and in contrast, the lowest number of species in both varieties of Vitis was detected in the 1994 season.