To determine the relationship between subjective sensation of nasal patency and objective measurement of nasal inspiratory peak flow rate, a longitudinal study was conducted using healthy volunteers. Five healthy medical practitioners, one woman and 4 men, aged 24-34 years, made daily subjective estimations of their sensation of nasal patency on a 10-cm visual analogue scale. This was followed immediately by measurements of nasal inspiratory peak flow rate using a Youlten meter, repeated on at least 25 days per subject. Correlation coefficient and regression lines for subjective nasal patency on nasal inspiratory peak flow rate were calculated. One hundred and sixty nine sets of observations were made, range 25-44 per subject. Each subject showed strong evidence (P < 0.01) of positive correlation between subjective nasal patency score and nasal inspiratory peak flow rate. There was strong evidence (P < 0.001) that different regression lines are needed for different subjects, but no evidence that the lines are not parallel. Subjective sensation of nasal patency is strongly correlated with objective nasal patency, as measured by peak inspiratory flow rate. This relationship varies between individuals. Measurement of nasal inspiratory peak flow rate may be a valuable objective test of nasal patency, and is quick and simple to perform.