The economic threshold level for the green semilooper,Chrysodeixis acuta(Walker) (Lepidoptera: Noctuidae) was determined on soybean cultivar JS 72–44 during 1986 in Madhya Pradesh, India. With an increase of every 1 larva/mrl (meter row length) at 45 d.a.e. (days after emergence) (flower initiation stage) and at 66 d.a.e. (pod filling stage), there were reductions of 593 and 662 kg/ha in grain yield, respectively. The yield loss caused by 3 to 18 larvae/mrl at flower initiation ranged from 7.29% to 45.51%, and that at pod filling ranged 9.43% to 46.49%. The control measures should be adopted at economic threshold level of three larvae and 2 larvae/mrl at flower initiation and pod filling stage of the crop, respectively.