Candida albicans has a number of transcriptional regulatory circuits that control aspects of cell type and cell morphogenesis. Recent work has uncovered a cryptic mating-type locus, and a variety of transcription factors that are important in regulation of the transition from yeast growth to hyphal growth. In some cases, the signalling pathways regulating these transcription factors are becoming defined. Analysis of phenotypic switching implicates internal factors, as well as external signals, in control of cellular morphogenesis.