Nitrogen dioxide (NO₂) is an oxidant gas that may injure the airway epithelial lining, leading to decrements in barrier and active ion transport properties. The present studies examined alterations of bioelectric properties and solute flux by guinea pig tracheobronchial epithelial (CPTE) monolayers exposed in vitro to NO₂. Confluent CPTE monolayers were exposed to NO₂ levels between 0.5 and 5 ppm, while controls were exposed to air. Following exposure, monolayers were mounted in Ussing chambers for measurement of transepithelial resistance (R_te) and short‐circuit current (SCC). A 1‐h exposure to 1 ppm NO₂ significantly increased SCC to 131.3 ± 8.7% of air controls, while R_te with a value of 109.3 ± 13.8% was unchanged. In contrast, a 1‐h exposure to 2 or 5 ppm NO₂ significantly decreased R_te to 39.0 ± 1.6 or 35.5 ± 7.3% of ah controls, respectively, while SCC values of 140.3 ± 10.4 or 153.3 ± 8.6%, respectively, were also significantly elevated. A 1‐h exposure to 2 or 5 ppm NO₂ significantly increased sucrose permeability across CPTE monolayers to 446.8 ± 117 or 313.3 ± 39.5% of air controls, respectively, while glycerol permeability was unchanged. In contrast, a 1‐h exposure to 1 ppm NO₂ produced no alterations of sucrose or glycerol flux. The SCC of control CPTE monolayers (1‐h air exposure) consisted of 50% bumetanide‐sensitive and 40% amiloride‐sensitive current; exposure for 1 h to 2 ppm NO₂ led to no changes in the corresponding SCC components. Active ion transport (i.e., SCC) across the airway epithelium was significantly increased after exposure to NO₂ levels <,1 ppm with no change of paracellular pathways for diffusion, suggesting that this reactive gas alters cell membrane function. The increased SCC may lead to impairment of fluid balance and mucociliary clearance. NO₂‐mediated tissue injury with levels >2 ppm primarily affects passive airway epithelial barrier functions, probably by altering tight junctions, which could result in increased transepithelial solute and fluid leakage in vivo.