The aim of this study was to evaluate the reliability and validity of the nasometer in diagnosing hypernasality in cleft palate patients. For this purpose the results of the nasometric examination of 30 patients with hypernasality were compared with the results obtained by using the currently taught methods. Sensitivity and specificity of nasometry were high with coefficients, respectively, of 0.80 and 1.00. Overall accuracy reached 0.90. Our results, which correspond almost exactly to those obtained in similar Anglo-American studies, demonstrate that also in German-speaking countries the nasometer can be a reliable instrument for diagnosing hypernasality. Moreover, the nasometer presents the possibility of calculating the extent of hypernasality during routine examination and diagnosis.