Nasal mucosal temperature was measured in 71 healthy subjects with an electronic thermometer. No correlation was found between the nasal mucosal temperature and age or sex. An increased mucosal temperature was found in patients with acute rhinitis, an effect which is supposed to assist in the defence system against microorganisms. When measuring nasal mucosal temperature over a 7-h period at the same time as nasal airway resistance, there was no correlation between these factors, indicating that the temperature is independent of the state of the capacitance vessels.