Candida glabrata is an opportunistic fungal pathogen that has become increasingly frequent in bloodstream and mucosal infections in immunocompromised patients. C. glabrata is phylogenetically more closely related to S. cerevisiae than to C. albicans, and some well identified virulence factors in C. alhicans do not seem to be conserved in C. glabrata. However. other important traits are shared by both organisms, and these may play a role in the adaptation and survival in the host as opportunistic pathogens. Both species adhere tightly to host cells, and C. globrata has a large family of subtelomeric genes encoding cell surface proteins that mediate this adherence. Expression of these genes is regulated by a chromatin-based negative regulation termed subtelomeric silencing. C. albicans also possesses several adhesins although they are not regulated by this mechanism. C. albicans and C. glabrata have been considered asexual, but recent work has demonstrated the existence of a cryptic sexual cycle in C. albicans. The fact that C. glabrata contains all of the genes essential for mating suggests the possibility that C. glabrata might also have a tightly regulated sexual cycle. Both organisms can form biofilms and can undergo phenotypic switching which could be important for rapid adaptation to the changing environmental conditions encountered in the host as opportunistic pathogens.