We examined the relation of dietary diversity to subsequent all-cause mortality by using data from the First National Health and Nutrition Examination Survey (NHANES I) Epidemiologic Follow-up Study, 1982-1987. The analytic cohort consisted of 4160 men and 6264 women (including 2556 deaths), 25-74 y at baseline (1971-1975). Twenty-four-hour dietary recalls were evaluated for variety among the five major food groups: dairy, meat, grain, fruit, and vegetable, with a dietary diversity score (DDS); consumption of each food group contributed 1 point to a maximum possible DDS of 5. Age-adjusted risk of mortality was inversely related to DDS (P < or = 0.0009) in men and women. The inverse diversity-mortality association was adjusted for potential confounders: education, race, smoking status, and dietary fiber intake; the relative risk of mortality in men and women consuming two or fewer food groups was 1.5 (95% CI 1.2-1.8) and 1.4 (95% CI 1.1-1.9), respectively. In conclusion, diets that omitted several food groups were associated with an increased risk of mortality.