286 normal subject representing both sexes and seven age groups from 10 to greater than or equal to 70 years were tested with both conventional pure tone audiometry and high frequency audiometry (4--20 kHz) using a previously described free field system. The subjects were selected according to very strict criteria. Results from conventional audiometry are similar to other findings in presbycusis studies, though sex difference was seen for the oldest age groups, but only at the frequencies 4 and 5 kHz where the male population showed a significantly poorer hearing. The same sex difference was observed by high frequency audiometry at 4 and 8 kHz. From 10--20 kHz no sex difference was present. At the high frequencies there is an abrupt decrease in hearing sensitivity already from youth. Hitherto, no international standard for zero dB hearing level exists for frequencies above 8 kHz. It is questioned whether a general standard is meaningful at all and that normative data for various age groups should instead be used as a reference level.