Rationale : Secondary bacterial infection following rhinovirus (RV) infection has been recognized in chronic obstructive pulmonary disease. Objectives: We sought to understand mechanisms by which RV infection facilitates secondary bacterial infection. Methods : Primary human airway epithelial cells grown at air-liquid interface and human bronchial epithelial (16HBE14o-) cells grown as polarized monolayers were infected apically with RV. Transmigration of bacteria (nontypeable Haemophilus influenzae and others) was assessed by colony counting and transmission electron microscopy. Transepithelial resistance (R T ) was measured by using a voltmeter. The distribution of zona occludins (ZO)-1 was determined by immunohistochemistry and immunoblotting. Measurements and Main Results : Epithelial cells infected with RV showed 2-log more bound bacteria than sham-infected cultures, and bacteria were recovered from the basolateral media of RV-but not sham-infected cells. Infection of polarized airway epithelial cell cultures with RV for 24 hours caused a significant decrease in R T without causing cell death or apoptosis. Ultraviolet-treated RV did not decrease R T , suggesting a requirement for viral replication. Reduced R T was associated with increased paracellular permeability, as determined by flux of fluorescein isothiocyanate (FITC)-inulin. Neutralizing antibodies to tumor necrosis factor (TNF)-a, IFN-g and IL-1b reversed corresponding cytokine-induced reductions in R T but not that induced by RV, indicating that the RV effect is independent of these proinflammatory cytokines. Confocal microscopy and immunoblotting revealed the loss of ZO-1 from tight junction complexes in RV-infected cells. Intranasal inoculation of mice with RV1B also caused the loss of ZO-1 from the bronchial epithelium tight junctions in vivo. Conclusions: RV facilitates binding, translocation, and persistence of bacteria by disrupting airway epithelial barrier function.