Enzymes are important industrial catalysts whose use has evolved from simple degradation processes - conducted mostly with hydrolases dissolved in the aqueous reaction medium - to processes of organic synthesis in which different classes of enzymes catalyze more complex reactions in different catalyst formats and reaction media. Extending the use of enzymes from the former low added-value processes to ones in which added-value is considerable is an exciting opportunity for biocatalysis; however, converting these remarkable physiological catalysts into robust process catalysts represents a complex technological challenge. Impressive advances both in enzyme production and enzyme molecular (re)design has opened a whole new field of enzyme use that projects into the fine chemicals and pharmaceutical industries where the outstanding properties of enzymes in terms of molecular precision are highly appreciated. Enzyme processes are compliant with green chemistry principles representing another important asset of biocatalysis. This chapter describes the evolution of enzyme catalysis, its present status and future prospects. Special emphasis is made on its impact on processes of organic synthesis and in non-conventional reaction media. Advances in the field related to the use of enzymes as industrial catalysts as well as the present and future challenges are analyzed in a hopefully unbiased perspective.