The present study was designed to investigate the efficacy of four classes of insecticides: pyrethroids, organophosphates, phenyl-pyrazoles and neo-nicotenoids, which were tested for their LC50 values against three strains of Periplaneta americana (Linnaeus) under topical and contact glass jar methods. Strain 1 was found to be highly resistant while least resistant was strain 3 with very low LC50 values for all insecticides. Imidacloprid 5%SC was highly effective at all concentrations applied for topical and glass jar methods, while DDVP 50% EC was least toxic for both methods. One way ANOVA...