This chapter reviews many of the characteristics of elastin and discusses several recent findings related to its regulation, interaction with cells, gene structure, and assembly. The understanding of elastin structure and elastic fiber assembly and function is expanding rapidly because of advances in cell and molecular biology. The recent characterization of the elastin gene has provided the tools with which to delineate the cellular controls of elastogenesis. The precise developmental expression of tropoelastin makes this an appropriate model for studying tissue- and temporalspecific regulation at the molecular level. Progress should be made in coming years on describing these mechanisms, and on determining the contribution of different regulatory processes to the control of elastogenesis. In addition, new in vitro models are being developed by many laboratories that can be used to delineate the influence of various factors and conditions on elastin-producing cells. Such models will provide further insights into the mechanisms by which cells interact with, and are influenced by, the extracellular matrix.