A multivitamin/mineral supplement is the most widely used type of dietary supplement among American adults. Therefore, accurate assessment of intake from this supplement is crucial when studying diet and chronic diseases. From 1999 to 2001, the Multiethnic Cohort Study collected detailed information on multivitamin/mineral use among five ethnic groups: African Americans, Native Hawaiians, Japanese Americans, Latinos, and whites. Daily nutrient intakes from multivitamin/minerals were calculated using the nutrient composition specified on the product label. For reported supplements with insufficient detail to match to a specific product, default nutrient profiles were assigned. Multivitamin/mineral use was reported by 50% of the participants (38% for Native Hawaiians to 57% for whites). Default profiles were assigned for 38% of users. The median daily nutrient intakes from multivitamin/minerals among users (n=75,865) were well above the Recommended Daily Allowance or Adequate Intake for vitamins A, B-6, B-12, and E, thiamin, riboflavin, niacin, pantothenic acid, folate, and zinc. Although nutrient intakes from multivitamin/minerals varied widely among individuals, there was no substantial difference in the median intake across ethnic groups. To accurately estimate nutrient intakes from multivitamin/minerals, detailed information on the product consumed should be collected. When detailed information is not available, the same default nutrient profiles can be used when estimating intakes for these five ethnic groups.