Researchers have estimated differential mortality across socioeconomic groups by classifying individuals using income in the previous year. The first problem with this strategy is reverse causation. Second, annual income is a noisy measure of permanent income. This paper tackles these two drawbacks by using better measures of lifetime earnings from administrative records to classify individuals. Results indicate that the relationship between mortality and lifetime earnings is very strong, is weaker for women than for men, varies when individual versus household earnings is used, is less pronounced at older ages, and has become substantially stronger in the last 20 years.