The Supplement Reporting (SURE) study is one of the first to systematically examine the accuracy of collection of dietary supplement use data for population-based studies of diet. In 2005-2007, the SURE study collected data from 444 participants in Hawaii and Los Angeles. Several methods of collecting data were compared, including an inventory of supplements, a recall, a daily diary, and a one-page supplement frequency questionnaire. Considerable effort was put into developing an extensive supplement composition database. To quantify intakes, we extended the existing supplement composition table (SCT) used at the Cancer Research Center of Hawaii. The original SCT contained default codes for multivitamin/multimineral products to be used when insufficient detail was available to assign an existing code. However, the default concept needed to be expanded for the SURE study to include additional multivitamin/multimineral default codes, as well as single nutrients and other components. Approximately 1800 new codes were created, including 211 new default codes. Roughly 130 nutrients and 870 other components were included in the SCT at the conclusion of the study. To accurately quantify intakes from supplements, it is crucial to maintain a comprehensive supplement composition database. Future improvements to our SCT include incorporation of analytic values from the US Department of Agriculture to replace composition data taken from supplement labels.