In this investigation, the corrosion performance of a commercial sintered Nd-Fe-B magnet in a cell culture medium, and the cytotoxic response due to the magnet corrosion products leached into the cell culture medium, have been studied. Localized corrosion was observed and the corrosion products leached into cell culture medium were analyzed by ICP-OES. The magnet showed no toxicity in the neutral red uptake assay used in this investigation contradicting results from literature obtained by another method of cytotoxicity assay.