Over the last ten years a resurgence of bed bugs has been reported in many parts of the world. In some metropolitan areas of the United States there are reports of at least tenfold increase in the number of infestations. The chemical arsenal for control of bed bugs is limited, with pyrethroid insecticides being the mainstay. Despite their wide use, there is no published information on pyrethroid susceptibility in natural populations. Bed bugs collected from human dwellings in Cincinnati (OH) and Lexington (KY) were reared under laboratory conditions using a warm membrane feeder with chicken blood. Progeny from these field populations were exposed as adults to filter paper discs that had been treated with technical grade deltamethrin or lambda-cyhalothrin in acetone. Extremely high levels of resistance to deltamethrin (>12,765-fold) and lambda-cyhalothrin (>6,123-fold), relative to a susceptible strain, were detected in populations from both states. Offspring of a cross between a resistant and susceptible strain had intermediate susceptibility, but still showed a 1,481 resistance ratio for deltamethrin. Evaluations of populations from across the United States indicate that resistance to pyrethroid insecticides is already widespread. Without the development of new tactics for bed bug management, further escalation of this public health problem should be expected.