An event of SIGMA /sup -/ production was observed among 40.000 pictures taken of 8.3 plus or minus 0.6 Bev/c pi /sup -/ interactions in a propane chamber with a constant magnetic field of 13,700 gauss. The picture and scheme of the event are shownwn-n. At the zero point the pi /sup -/ forms a star of four prongs with high energies. The more probable reaction in the first star is considered to be pi /sup -/ + C yields SIGMA /sup -/ + K/sup 0/ + K/sup 0/ + K/sup -/ + p + pi /sup +/ + pi /sup -/ + recoil nuclei. The lifetime of SIGMA /sup -/ is (1 18 plus or minus 0 07) x 10/sup -10/ sec. (R.V.J.)