Vibration perception threshold (VPT) is increasingly used as a measure of large nerve fibre function in studies of patients with diabetes and in other disorders. In order to establish the influence of age, height, sex, and smoking on VPT values in the normal population and to allow the calculation of accurate age-related percentile charts, 1365 healthy volunteers were studied using a biothesiometer. Measurements were made bilaterally on thumbs, great toes, and over medial malleoli. Multivariate regression analysis confirmed age to be the major determinant of VPT levels at all sites (p less than 0.001). Height was a significant factor for toes and ankles (p less than 0.001) but not thumbs. Sex had no overall effect at toe or thumb but there were differences regarding ankle VPT (p less than 0.01). Log transformation of VPT data produced a linear relationship with age at all sites except at the thumbs in elderly females where there was significant deviation from this model (p less than 0.001) and inverse square root transformation was more appropriate. Smoking had no effect on VPT levels. Age-related centile charts were produced for each site and an easy-to-use computer program was developed to calculate centile values based on raw VPT data, age, height, and sex.