The purpose was to examine the relationship between performance in the 400-meter walking test and mortality. Data are from a population-based sample of 948 Italian men and women > or =65 years. The main outcome measures that were assessed comprised time to complete the 400-meter walk, 20-meter lap time coefficient of variation, need to rest during the test, and ability to complete the walk. All-cause mortality was ascertained over a 6-year follow-up period. Data were analyzed with proportional hazard logistic and linear regression analyses. In age- and sex-adjusted analyses, all 400-meter walking test variables except need to rest were associated with mortality. After further adjusting for the Mini-Mental State Examination, symptoms of depression, education, smoking, body mass index, being sedentary/minimally active, disease burden, and lower extremity performance (Short Physical Performance Battery score), both time to complete the 400-meter walk and lap time coefficient of variation were significant independent predictors of mortality. We conclude that multiple aspects of performance in the 400-meter walk test provide complementary information on mortality prognosis in older persons.