Two knee height equations to predict standing height of Japanese elderly were cross-validated with Joetsu City elders. One equation was derived with Hawaiian residents of Japanese ancestry and the other with elders from the Kumamoto Prefecture in Japan. Subjects included 40 men and 39 women free-dwelling, healthy elders with mean ages of 68.0 +/- 2.2 years and 68.0 +/- 2.7 years, respectively. Heights of the subjects were representative of Japanese elderly. Experienced nurses, trained to measure knee height, also measured standing height with an automatic stadiometer. A pilot study refined measurement skills. Differences between actual and predicted heights for both equations were significant. Multiple linear regression was used to derive knee height equations specific for elderly males and females living in Joetsu City women, 63.06 + (2.38 x knee height in cm) -(0.34 x age in years); men, 71.16 + (2.61 x knee height in cm) - (0.56 x age in years). Geographic-specific knee height equations for Japanese elderly and cross-validation with other locations are suggested to facilitate the accurate use of knee height in nutritional assessment of Japanese elders.