To provide a lecithinized superoxide dismutase (PC-SOD) composition useful as a drug material and a process for its production. The PC-SOD composition contains a PC-SOD obtained by substituting at least amino group in a specific SOD with a lecithin moiety represented by the following formula (I), wherein the PC-SOD contains a PC-SOD (A) having an m number of amino groups substituted with the lecithin moieties (wherein m is an integer of from 1 to 4 and averages from 1.5 to 2.4 as a main component and the PC-SOD (A) consists of a PC-SOD (a1) wherein m=1, a PC-SOD (a2) wherein m=2, a PC-SOD (a3) wherein m=3 and a PC-SOD (a4) wherein m=4. ##STR00001##