Triceps skinfold thickness and body weight measures were obtained for 44 female and 40 male mentally retarded adults participating in a sheltered workshop setting. Subiects' relative weights and skinfold thicknesses were found to correlate reasonably well for females and males, rs = .88 and .59, respectively. Use of only height and weight tables for determining the presence of obesity, however, resulted in 22.5 percent of the males and 13 .7 percent of the females being misclassified as nonobese. The distinction between overweight and obesity was discussed. Clinical/research implications of the findings were delineated.