The aim of this study is to estimate the contributions of changes in population distribution by marital status to the changes in adult mortality in six developed countries. The change in total mortality was decomposed into the contributions of: (i) mortality changes within each marital status category; and (ii) changes in population composition by marital status. The study provides evidence that changes in population composition contributed to increases in male mortality in Russia and Lithuania, whereas in the remaining male populations this was a significant obstacle for faster health improvements. The compositional changes had only small impacts on female mortality.