Technical Abstract: Strains of the tobacco budworm, Heliothis virescens (F.), collected in Mississippi in 1993 through 1995 were evaluated in bioassays to four classes of insecticides and Bacillus thuringiensis Berliner. High levels of resistance were found to cypermethrin, methomyl, and thiodicarb. Resistance to the organophosphorus insecticide profenofos was found in several strains. Significant resistance to B. thuringiensis Berliner was observed in one strain. Possible synergism of a pyrethroid in combination with the synergist piperonyl butoxide was observed. Imidacloprid, representing a new class of insecticide, was found to have ovicidal and larvacidal activity on H. virescens. Multiple resistance is still apparent and cross-resistance is present to carbamate insecticides. Resistance to pyrethroids appears to be stabilized at a high level.