Abstract Bioelectrocatalysis is concerned with the use of biological materials as catalysts for electrochemical processes. Of particular value in this context are those enzymes that catalyse oxidations and reductions. These often have or require cofactors, other proteins or coenzymes, involved in the electron transfer steps. The attainment of rapid electron transfer between the enzymes or the cofactors and an electrode is essential for the success of bioelectrocatalysis. This can be achieved either directly or indirectly by using mediators of electron transfer. The factors influencing the rates of the reactions at electrodes are described and potential applications to electroenzymological syntheses and biofuel cells are discussed.