Because diet is closely related to cancer incidence and mortality, recent studies in cancer epidemiology have focused on dietary factors. The results of studies on nutritional cancer epidemiology in Korea are discussed in this research paper. Most studies have used a case-control design focused on breast or gastric cancer patients. Antioxidants were associated with a reduced risk of gastric cancer in most studies, but this association was not observed for breast cancer. Most diets consumed by Koreans that included fruits and vegetables were associated with reduced cancer risk, but high concentrations of salt in food were positively associated with gastric cancer risk. Genetic susceptibility was considered in several studies, and food contaminants were assessed to estimate life-time cancer risk. Recent studies have made advances in understanding the relationship between diet and cancer among Korean populations. However, because the history of nutritional cancer epidemiology in Korea is relatively short, the subjects covered and methodology of the research have been limited. A cohort design with a large sample size and appropriate methods to assess subjects’ usual intake may be needed to determine the true association between diet and cancer in the future.