The gaseous phytohormone ethylene regulates many aspects of plant morphogenesis. Growth and development of cells cultured in vitro are largely dependent on the presence of phytohormones, including ethylene in the culture environment. Hence, modification of phytohormone composition and interaction in the nutrient medium has been the primary strategy to manipulate morphogenesis in vitro. Such studies have shown the importance of ethylene, as well as the inhibition of its synthesis or action, in growth and organized development in vitro, including xylogenesis, organogenesis, somatic embryogenesis, and androgenesis. More recently, mutants and transgenic plants have been used to elucidate the role of ethylene in various cellular and developmental processes. In this review, we concentrate on the more recent advances in the study of ethylene in plant morphogenesis in vitro. We also include information about the various chemical modulators of ethylene biosynthesis and action employed in plant tissue culture.