OBJECTIVES: To assess the association between Dietary Diversity Scores (DDSs, range: 0-6 points) and medical service utilization and expenditures. STUDY DESIGN: Prospective cohort study. METHODS: The Elderly Nutrition and Health Survey in Taiwan (1999-2000) provided a 24-hour dietary recall for DDSs. National Health Insurance claims were linked for 1650 eligible elders. Generalized linear models were used to appraise the association between DDS and annual medical utilization and expenditures. RESULTS: Those with a higher DDS had lower medical service utilization and expenditures for emergencies and hospitalization. After adjustment for potential confounders, emergency and hospitalization expenditures for elders with a DDS of 6 were lower than those with a DDS of 3 or lower. However, for preventive care and dental services, the highest DDS of 6 predicted greater utilization (0.25 and 0.5 times) and expenditure (270 and 420 Taiwanese new dollars). Findings remained unchanged when those who died in the first year or had any medical utilizations and expenditures1 year prior to death were excluded. CONCLUSIONS: Greater dietary diversity is associated with lower emergency and hospitalization utilization and expenditures, but not lower use of ambulatory services. There is a need for health services to develop a nutrition policy for nutritionally disadvantaged groups.