Dietary supplement use is widespread among adults across races/ethnicities, yet reasons for use may vary across these groups. The SUpplement REporting (SURE) study quantified dietary supplement use and reasons for taking supplements in a multiethnic sample of adults who took at least one supplement. This study explored socio-demographic differences, including by race/ethnicity, associated with specific reasons/motivations for taking dietary supplements, including perceived importance of taking supplements relative to prescription medications. The study time period was March 2005 to August 2006. Participants (n=397) were older adults (age = 52–88 y) recruited from the Multiethnic Cohort Study in Hawaii and Los Angeles, with equal representation of males and females from six ethnic groups (white, Japanese-American, Native Hawaiian, African-American, US-born Latino, and foreign-born Latino). Subgroups of participants were compared by chi-square tests and logistic regression. The most common reasons for taking supplements were to maintain a healthy life, recommended by a health professional, and to prevent a disease/medical problem. A majority (76%) of participants reported that their dietary supplements were as important as prescription medications, with foreign-born Latinos and Japanese-Americans being most likely to state this belief. The relative importance of supplements was not associated with excessive use, but 27% of participants exceeded the upper limit for a nutrient. It is crucial for health professionals to better understand why individuals take supplements and the importance that they attach to their use. This information could lead to better monitoring and education efforts in order to prevent overuse of supplements and possible interactions with medications.