Complexes of manganese have previously been shown to exhibit SOD activity. In this study, we tested the ability of several (salen)-manganese complexes to scavenge O2.. Both neutral and cationic complexes were determined to be SOD-mimics. The activity of the complexes was not affected by the presence of bovine serum albumin in the assay. For most compounds, the activity was inhibited by the addition of EDTA. The stability and high catalytic activity of some of these molecules suggest that they might have potential use in a variety of conditions which involve overproduction of oxygen free radicals.