The ion transport defects reported for human CF airways are reproduced in nasal epithelia of the CF mouse. While this tissue has been studied in vivo using the nasal potential difference (PD) technique and as a native tissue mounted in the Ussing chamber, little information is available on cultured murine nasal epithelia. We have developed a polarized cell culture model of primary murine nasal epithelia in which the CF tissue exhibits not only a defect in cAMP mediated Cl^- secretion but also the Na⁺ hyperabsorption and upregulation of the Ca⁺⁺ activated Cl^- conductance observed in human airways. Both the wildtype and CF cultures were constituted predominantly of undifferentiated cuboidal columnar cells, with most cultures exhibiting a small number of ciliated cells. Although no goblet cells were observed, RT-PCR demonstrated the expression of MUC5AC RNA after ~ 22 d in culture. The CF tissue exhibited an adherent layer of mucus similar to the mucus plaques reported in the distal airways of human CF patients. Further, we found that treatment of CF preparations with a Na⁺ channel blocker for 7 days prevented formation of mucus adherent to epithelial surfaces. The cultured murine nasal epithelial preparation should be an excellent model tissue for gene transfer studies and pharmacologic studies of Na⁺ channel blockers and mucolytic agents, as well as for further characterization of CF ion transport defects. Culture of nasal epithelia from F508 mice will be particularly useful in testing drugs that allow F508 CFTR to traffic to the membrane.