A genetic analysis of secretory pathway function in yeast was initiated some 12 years ago in the laboratory of Randy Schekman. These mutants held great promise in terms of providing an experimental system with which molecular participants of secretory pathway function could be investigated. This early promise has not failed. For the last five years, analysis of yeast secretory pathway function has been at the cutting edge of our understanding of the mechanisms by which proteins travel between intracellular compartments. In some cases, Sacch. cerevisiae has provided a valuable in vivo corroboration of the concepts derived from biochemical studies of mammalian intercompartmental protein transport in vitro. In other cases, studies conducted in the yeast system have defined previously unanticipated involvements for known catalytic activities in the secretory process. It is clear that yeast will continue to play a major role in setting the pace of research directed towards a detailed molecular understanding of protein secretion. Since it is now apparent that the basic strategies that underlie secretory pathway function have been conserved among eukaryotes, further exploitation of the powerful and complementary yeast and mammalian experimental systems guarantees that the next decade will see even greater progress towards our understanding of protein secretion in eukaryotic cells than did the first.