The diamondback moth, Plutella xylostella (Lepidoptera: Yponomeutidae), is a serious threat to Brassica vegetables in Iran, including Tehran province. The ovicidal effects of different classes of insecticides on P. xylostella were investigated, using three fixed doses (based on commercial formulations). At the lowest concentration (500 mg L-1), the mortality effect of hexaflumuron and pyridalyl was higher than the other insecticides examined. Fipronil, hexaflumuron and spinosad and pyridalyl, however, showed high toxic effects at the median dose (1000 mg L-1). On the other hand, at high concentration (2000 mg L-1), all insecticides except lufenuron and indoxacarb (EC formulation) caused more than 85% mortality. Overall, these findings indicate that hexaflumuron, spinosad and fipronil, with low active ingredients and high mortality, could be the best choices for controlling the P. xylostella in the egg stage.