This review focuses on recent studies investigating the genetic regulatory mechanisms leading to formation of morphologically, functionally, and molecularly distinct cardiac chambers. The regulation of four representative chamber-specific genes that have been studied in detail is reviewed. These genes include the atrial-specific genes, myosin light chain-2a (MLC2a), slow myosin heavy chain-3 (slow MyHC3), and atrial natriuretic factor (ANF) and the ventricular specific gene, myosin light chain-2v (MLC2v). Comparison of these promoters reveals some generalizations about the regulatory mechanisms involved in chamber-specific gene expression but, equally, indicates the large gaps in the knowledge concerning this intriguing genetic program