Although there is an increasing trend of dietary supplement (DS) use, few researches have evaluated nutrient intake from DS. This study aimed to establish a nutrient database (NDB) for DS and estimate the effect of DS on total nutrient intake by Korean adults. The NDB for DS was established using the label information of products reported in the Korea National Health and Nutrition Examination Survey (KNHANES) IV. Of the 16,031 participants who were ≥20 years old, 2053 products were reported as being taken by 5606 subjects. But nutrient composition could be identified by searching product name only in 1158 products consumed by 3844 subjects (DS users). Total nutrient intake of DS users was obtained by combining intakes from diet and DS. Dietary supplement use was higher in women, in middle-aged people and in those with higher education and low smoking and drinking preferences. Nutrients obtained from food were higher in DS users than in nonusers for most nutrients, particularly in women. When total nutrient intake was evaluated in DS users, the percentage of subjects whose intake was below the estimated average requirement for Koreans decreased for several vitamins and minerals, but the percentage of subjects whose intake was above the tolerable upper intake levels increased for vitamin A, vitamin C and iron. The newly developed NDB for DS will be an important resource for more accurate assessment of nutrient intake as well as evaluation of the relationship between nutrition and health. Further research is needed to update a more comprehensive NDB applicable to diverse populations.