Quorum sensing is a cell-density effect and the regulation of gene expression in response to extracellular chemical signals(quorum-sensing molecules)produced by microorganisms. Hyphal induction in Candid albicans is inhibited by high cell density and also by farnesol, which is a quorum-sensing molecule of the organism. Here, we describe models of the regulation of dimorphism in Candida albicans by farnesol from the latest published data and gene regulation during the initial stages of quorum sensing, which was obtained through microarray analysis.