Recent studies of the insulin gene promoter and the transcription factors that regulate it have expanded our understanding of both how the production of insulin is restricted to the pancreatic beta -cell, and how that production is regulated by physiologic signals such as glucose. A picture is emerging in which an elaborate set of transcription factors binds to specific sequences along the promoter and recruits additional transcriptional co-activators to build a functional transcriptional activation complex that is unique to beta -cells. Surprisingly, however, genetic experiments in mice have demonstrated an unexpected degree of redundancy in the factors that control insulin gene expression, and have revealed the presence of a network of transcription factors that coordinate the expression of factors forming the insulin gene activation complex.