|Defensins are a family of endogenous antibiotics that are important in mucosal innate immunity, but little is currently known about defensin expression in the nasal cavity. Herein expression of canine β-defensin (cBD)1, cBD103, cBD108 and cBD123 RNA in the respiratory epithelium (RE), cBD1 and 108 RNA in the olfactory epithelium (OE), and cBD1, cBD108, cBD119 and cBD123 RNA in the olfactory bulb (OB) is reported. cBD1 and 103 were also expressed in the canine nares and tongue. cBD102, cBD120, and cBD122 RNA expression was undetectable in the tissues examined. cBD103 transcript abundance in canine nares showed a 90 fold range of inter-individual variation. Murine β-defensin 14 expression mirrors that of cBD103 in the dog, with high expression in the nares and tongue, but has little to no expression in the RE, OE or OB. High expression of cBD103 in the nares may provide indirect protection to the OE by eliminating pathogens in the rostral portion of the nasal cavity, whereas cBD1 and 108 may provide direct protection to the RE and OE.