A new method for the purification of manganese superoxide dismutase from human liver is described. The procedure involves essentially three steps: DEAE-cellulose, hydroxylapatite, and butyl-Toyopearl chromatographies. The method has several advantages: (i) its simplicity and rapidity (it takes less than 3 days), (ii) its high yield (62%) with a high specific activity (5660 units/mg of purified SOD), and (iii) its suitability for both large- and small-scale purifications.