Technical Abstract: Recent epidemiologic studies assessing tree nut (almonds, Brazil nuts, cashews, hazelnuts, macadamia nuts, pecans, pine nuts, pistachios, and walnuts) consumption and the association with nutrient intake and diet quality are lacking. This study determined the association of tree nut consumption and nutrient intake and diet quality using a nationally representative sample of adults. Adults 19+ years (y) (n equals 13,292) participating in the 1999-2004 National Health and Nutrition Examination Survey were used. Intake was determined from 24-hour diet recalls; tree nut consumers were defined as those consuming greater or equal to 1/4 ounce/day (7.09 g). Means, standard errors, and ANOVA (adjusted for covariates) were determined using appropriate sample weights. Diet quality was measured using the Healthy Eating Index-2005. Among consumers, mean intake of tree nuts/tree nut butters was 1.19 + 0.04 oz/d versus 0.01 + 0.00 oz/d for non-consumers. In this study, 5.5 +/- 0.3 % of individuals 19-50 y (n equals to 7,049) and 8.4 +/- 0.6 % of individuals 51+ y (n equals to 6,243) consumed tree nuts/tree nut butters. Mean differences (p less than 0.01) between tree nut consumers and non-consumers of adult shortfall nutrients were fiber (+5.0 g/d), vitamin E (+3.7 mg AT/d), calcium (+73 mg/d), magnesium (+95 mg/d), and potassium (+260 mg/d). Tree nut consumers had lower sodium intake (-157 mg/d, p less than 0.01). Diet quality was significantly higher in tree nut consumers (58.0+/-0.4 vs. 48.5+/-0.3, p less than 0.01). Tree nut consumption was associated with a higher overall diet quality score and improved nutrient intakes. Specific dietary recommendations for nut consumption should be provided for consumers.