This is the first study to investigate how food and nutrient intakes vary with the levels of acculturation of Korean Americans using a dietary assessment tool tested for validity and reliability. The respondents were Korean Americans (n 486) resident in the Greater New York metropolitan area, USA. They were divided into two groups according to the total score of acculturation: low- and high-acculturated groups. Using a food-frequency questionnaire and a modified Suinn-Lew Asian self-identity acculturation scale, differences in the frequencies of food items, food groups and nutrient intakes consumed were analysed by level of acculturation. The low-acculturated group tended to consume significantly more rice, mixed rice, soyabean paste chigae (pot stew), saengsun (fish) chigae, kimchi chigae, other fish broiled or baked, eggs, kimchi, spinach, persimmons, and white or brown sugar in coffee or tea. The high-acculturated group demonstrated a statistically greater tendency to consume bread, cereal, spaghetti, ham, green salad, sweetcorn, chocolate, candies and diet soft drinks. The more acculturated an individual, the more significant was the tendency to consume sweets. The more acculturated group had significantly (P<0·05) higher intakes of % energy from total fat, thiamin, vitamin E and folate, while the low-acculturated group consumed greater amounts of Na, niacin and dietary fibre. The information from the present study can be used to describe dietary habits according to various aspects of acculturation, and allows a better understanding of the dynamics of acculturation and dietary habits.