1. Kidney weight was analysed for Japanese and New Zealanders of European origin who had died sudden deaths.
2. Kidney weight was relatively greater in Japanese than in New Zealanders.
3. Kidney weight was closely related to body surface area and weight and less closely to height and body mass index.
4. As kidney function is related to kidney size and thus in turn to body size it is advisable to take account of body size in analyses of sodium intake and excretion in relation to blood pressure.