The depth and composition of the airway surface liquid (ASL) must be strictly regulated to maintain an environment that is optimal for the activity of a variety of innate airway defence mechanisms that help to keep the lungs sterile. One way in which ASL is regulated is through the absorption of Na⁺ across the airway epithelium. Much previous work has investigated the mechanisms by which the Na⁺ channel (ENaC) itself is regulated, but less emphasis has been placed on the role of basolateral K⁺ channels, which maintain the electrical driving force for Na⁺ absorption by maintaining the membrane potential during absorption. We recently showed, for the first time, that K⁺ channels of the K2P subtype maintain resting levels of Na⁺ absorption in the H441 cell line (Inglis, S.K., et al., A Ba²⁺-resistant, acid-sensitive K⁺ conductance in Na⁺ absorbing H441 human airway epithelial cells. Accepted for pub. Am. J. Physiol., 2007). The aim of the current study was to investigate whether K2P channels maintain resting levels of ion transport in primary cultures of human nasal epithelial cells. Nasal cells were harvested from individuals undergoing unrelated surgery using a small nylon brush in a procedure approved by the local ethics committee. Cells were grown to approximately 70% confluence in a flask before being seeded onto collagen-coated porous supports (Snapwells, Corning, Inc.). After 14 days cells had formed resistive monolayers and were mounted in an Ussing chamber. Transepithelial potential (Vt) was monitored using a voltage clamp (WPI) attached to a computer via Powerlab interface (ADInstruments). One stable, Vt was clamped to 0mV and shortcircuit current (Isc) recorded. Mean Vt, Isc and resistance (Rt) were 2.2±2.5mV, 12.5±2.9µAcm^-2 and 285±112Ωcm² respectively (n=11). Amiloride and bumetanide (both 10µM) inhibited approximately 80% and 0% of Isc respectively (n=4). After imposing a basolaterally-directed K⁺ gradient and permeabilising the apical membrane with amphotericinB (200µM) bupivacaine (3mM) inhibited 24.4±5.1% of basolateral K⁺ current (P<0.05; n=3). Subsequent addition of Ba²⁺ (1mM) had no effect. Bupivacaine inhibited 15.4±2.4% of Isc in intact monolayers (n=3), this was not significant. These results suggest that primary cultures of human airway cells possess K2P channels that may help to maintain basal levels of ion transport.