Extracellular alpha- and-beta-galactosidases from a strain of Aspergillus niger were separated and purified in one step by cation exchange chromatography. Both enzymes had acidic pH (3.5-4.0) and high temperature (65-degrees-C) optima and an exceptionally high thermostability. Thus, -alpha-galactosidase had an activity half-time of 104 min at 60-degrees-C whereas at the same temperature the respective value for-beta-galactosidase was 835 min. At optimum conditions of activity the apparent K(m) values of alpha- and beta-galactosidase were 0.44mM and 1.1mM respectively. Both the high temperature optima and thermostability properties of the enzymes make them particularly suitable for high temperature processes.