The　superoxide　dismutase　(SOD)　family　of　proteins　are　necessary　to　protect　oxygen-utilizing　cells　from　the　toxicity　of　reactive　oxygen　species.　The　delivery　of　SOD　into　tissues　is　severely　limited　by　its　size　and　biochemical　properties.　A　cell-membrane-permeable　SOD,　SOD-TAT,　has　been　demonstrated　to　have　the　ability　to　be　directly　transduced　into　mammalian　cells.　In　this　study,　the　SOD-TAT　fusion　protein　was　expressed,　purified　and　crystallized.　Crystals　of　the　SOD-TAT　fusion　protein　diffracted　to　3.20　angstrom　resolution　and　belonged　to　space　group　C121.