Ae. Albopictus, Cx. Tritaeniorhynchus, Cx. Quinquefasciatus, Cx. Vishnui, four important vectors of dengue fever/dengue hemorrhagic fever, filariasis, Japanese encephalisis were collected from Lai Chau and Son La in July and October 2011. The patterns of insecticide susceptibility to alphacypermethrinm, deltamethrin, lambdacyhalothrin, permethrin, and malathion were determined. The results showed that: Ae. albopictus was found susceptibility to alphacypermethrin, deltamethrin, lambdacyhalothrin, permethrin and malathion. Cx. quinquefasciatus was found resistant to alphacypermethrin, deltamethrin, lambdacyhalothrin, permethrin (mortality, 60 - 76.6 percent), but malathion (mortality, 100 percent). Cx. tritaeniorhynchus was found resistant to alphacypermethrin, deltamethrin, lambdacyhalothrin, permethrin (mortality, 13 - 67 percent). Similarly, Cx. vishnui, was found resistant to alphacypermethrin, deltamethrin, lambdacyhalothrin, permethrin (mortality, 14.4 - 76 percent), exceptible in Ho Mit - Tan Uyen, tolerance to pyrethroids and malathion (mortality, 92 - 96 percent).