An earlier report showed significant differences among Huntington disease (HD) patients, controls, and particular age cohorts of at-risk persons for several dimensions of body mass and for several linear and craniofacial components of the body. In this investigation a function was derived from a stepwise discriminant analysis of the affected and unaffected groups, and used to classify the at-risk individuals according to HD gene carrier status. The function, comprised of body mass index, subscapular skinfold, head length, and sitting height, classified 95% of the controls and 87% of the affected individuals correctly. Approximately 80% of the individuals at-risk were classified with 80% or greater certainty. We propose that anthropometric variables may prove to be a powerful tool for basic research in HD and the derived discriminant function has potential clinical value as a diagnostic and preclinical diagnostic aid. We emphasize that corroborative testing on other sample populations of HD families is required before these techniques are utilized. Also, it is imperative that the anthropometric protocol include appropriate standardization of the raw measurement data.