Despite guidance to consume a variety of foods, the role of dietary variety in ensuring nutrient adequacy is unclear. The aim of this study was to determine whether a commodity-based measure of dietary variety was associated with the probability of nutrient adequacy after adjusting for energy and food group intakes. Subjects were 4969 men and 4800 women >/= 19 y old who participated in the Continuing Survey of Food Intakes for Individuals 1994-1996. Using 24-h recall data, the mean probability of adequacy across 15 nutrients was calculated using the Dietary Reference Intakes. Dietary variety was defined using a commodity-based method similar to that used for the Healthy Eating Index (HEI). Associations were examined in gender-specific multivariate regression models. Energy intake was a strong predictor of the mean probability of adequacy in models controlled for age, BMI, education level, and ethnicity (model R(2) = 0.60 and 0.54 for men and women, respectively). Adding the number of servings from each of the 5 Food Guide Pyramid (FGP) groups to the models significantly improved the model fit (R(2) = 0.69 and 0.66 for men and women). Adding dietary variety again significantly improved the model fit for both men and women (R(2) = 0.73 and 0.70, respectively). Variety counts within the dairy and grain groups were most strongly associated with improved nutrient adequacy. Dietary variety as defined by the HEI contributes an additional component of dietary quality that is not captured by FGP servings or energy intake.