[Objectives]  To meet the need for rapid bioassay methods for pesticide development and pest resistance monitoring, we compared the results obtained from bioassays using insect cells vs whole insects. [Methods]  The virulence of different pesticides to the Spodoptera frugiperda ovary cell line (Sf 9) and sensitive strains of Plutella xylostella was examined, and the correlation between the inhibition of the cell proliferation rate and insect mortality compared. [Results]  Both bioassay systems ranked the virulence of the three different types of insecticides as avermectin > imidacloprid > beta- cypermethrin, and the virulence of the five insecticides in the same category (organophosphorus) as > dichlorvos > phoxim > propionate > trichlorfon. Both bioassay systems also ranked the virulence of three formulations of the same insecticide (5% avermectin) as micro-emulsionn > emulsifiable concentrate > emulsion. A linear regression model of the relationship between an 8 h cell bioassay and 48h insect bioassay was constructed. [Conclusion]  The results of an 8 h cell bioassay were consistent with those of a 48 h insect bioassay. Cell bioassays provide a relatively quick way of testing new pesticides.