A sample of 104 patients, males and females between the ages of 6 and 16 years, was studied. The sample included patients with clinically diagnosed nasopharyngeal obstruction, patients with no obstruction, and random sample of patients for whom the presence or absence of obstruction was not known. More than 200 cephalometric measurements were used in an attempt to identify differences between the first two groups. Statistical t tests revealed four variables, all primarily related to adenoid size and nasopharyngeal dimensions, for which the mean values of the two groups were significantly different. Cephalometric norms for these four measurements were established, using the random sample patients, and these norms were calculated for various ages and both sexes. A method of identifying the degree of obstruction was then formulated on the basis of the four significant measurements. Preliminary results indicate that this method is highly correlated with observed clinical results.