Cellular membranes contain many types and species of lipids. One of the most important functional consequences of this heterogeneity is the existence of microdomains within the plane of the membrane. Sphingolipid acyl chains have the ability of forming tightly packed platforms together with sterols. These platforms or lipid rafts constitute segregation and sorting devices into which proteins specifically associate. In budding yeast, Saccharomyces cerevisiae, lipid rafts serve as sorting platforms for proteins destined to the cell surface. The segregation capacity of rafts also provides the basis for the polarization of proteins at the cell surface during mating. Here we discuss some recent findings that stress the role of lipid rafts as key players in yeast protein sorting and cell polarity.