The NIST Dietary Supplement Laboratory Quality Assurance Program (DSQAP) was established in collaboration with the National Institutes of Health (NIH) Office of Dietary Supplements (ODS) in 2007 to enable members of the dietary supplements community to improve the accuracy of measurements for demonstration of compliance with various regulations. Exercise I of this program offered the opportunity for laboratories to assess their in- house measurements of nutritional elements (Cr, Mo, and Se), contaminants (Cd), water-soluble vitamins (pantothenic acid), fat-soluble vitamins (retinol), and catechins in foods and/or botanical dietary supplement ingredients and finished products.