The delineation of specific erythrocyte glycolytic enzyme defects during the past three decades has clarified hitherto unexplained hereditary hemolytic syndromes. The glycolytic enzymopathies have proven to be important, not as a public health problem, but because the investigation of these experimental models of nature has provided information to increase our understanding of control of glycolysis and interrelationships of the Rapoport-Luebering shunt, mechanism of hemolysis, erythrocyte ageing, role of isozymes in various organs, and genetic control of enzyme structure/function. The application of ever improving techniques of recombinant DNA should yield a bonanza of new information to improve our comprehension of the pathogenesis and heterogeneity of these disorders as well as provide increased knowledge of regulation of these enzymes. It should be an exciting era.