This paper reports a simple rearing system for Cnaphalocrocis medinalis based on com seedlings diet. C. medinalis population under this system has been maintained by four stages (egg, young larva-1st to 3rd instar, old larva-4th to prepupa, and adult) at 25±2℃, 40±10% RH, and 16L:8D photoperiod in a laboratory. We have elaborated a new egg collection method using a polystyrene container (top Ø11.3 × bottom Ø9 × H8㎝) which has made a great contribution in easy collection of eggs and storage of them for long period. Under this system, pupation and adult emergence rate and pupal weight of C. medinalis population were close to the other reports by corn seedling diet and superior to those by artificial diets. Therefore this rearing system would be useful in obtaining C. medinalsis population suitable to each specific needs.