The Neurothesiometer is a new device designed to replace the Biothesiometer in screening for diabetic peripheral neuropathy by measuring vibration perception threshold (VPT). It was compared with the Biothesiometer in 85 diabetic patients, mean age 61 (range 21-82) years and mean duration of diabetes 12 (1-26) years, attending routine diabetes and foot screening clinics. VPT correlated with age and duration of diabetes (r = 0.46 and r = 0.42, respectively P < 0.01), with both devices. The Biothesiometer VPT was 29.9 +/- 15.2 V (mean +/- S.D.) compared with 26.2 +/- 13.4 V with the Neurothesiometer (P = NS) and there was a close correlation between the two devices r = 0.93 P < 0.001. The within patient coefficient of variation was 8.6% for the Biothesiometer and 8.1% for the Neurothesiometer. The Neurothesiometer gives results that are in close agreement with the Biothesiometer and has a good coefficient of variation in routine clinical use. It is a self contained, battery operated device, which, although more expensive than its predecessor, is well suited to diabetes screening programmes and would be particularly useful to epidemiological surveys in the community.