The nasal mucosal pH is approximately 5.5-6.5, and increases in rhinitis to 7.2-8.3. This knowledge has not led to the widespread measurement of the nasal mucosal pH as an objective clinical parameter. The purpose of this study was to assess whether repeatable measures of nasal mucosal pH could be obtained in the clinical setting. Fifty-four adults without nasal symptoms were prospectively recruited. Using a semi-disposable antimony pH catheter, the nasal mucosal pH was measured in four specific areas of the nose and each reading repeated three times. The patients' age, sex, smoking habits, nasal anatomical variation and clearest nostril at the time of measurement were also recorded. The data shows that it is possible to obtain reliable and repeatable values for the pH of the nasal mucosa (Spearman-Brown R = 0.84). Analysis shows there is no significant difference between septal and turbinate mucosal pH. Subset analysis implies that nasal mucosal pH is higher in men then women (P < 0.05). The other variables did not affect the nasal mucosal pH significantly.