BACKGROUND: Little is known about the effects of long-term marital history on mortality, and the relative importance of using marital history instead of baseline marital status in mortality analyses. No previous comparative studies on the associations of marital history and mortality exist. METHODS: Longitudinal data from England & Wales and from Finland were used to assess the effects of marital history, constructed from census records from years 1971, 1981 and 1991, on all-cause mortality in 1991-2004 among men and women aged ≥ 50 years. Data from England & Wales include 57,492 deaths; data from Finland include 424,602 deaths. Poisson regression analysis was applied. RESULTS: Adding marital history into models including baseline marital status was statistically significant when explaining male mortality, while it was generally not important for female mortality. Adjusted for socio-demographic covariates, those consistently married with no record of marital break-up had the lowest mortality rates among both men and women aged 50-74 in both countries. Those never married, those divorced with a history of divorce and those widowed with a history of widowhood showed the highest mortality risks. Associations between marital history and mortality were weaker among those aged 75+. CONCLUSIONS: Consistent evidence in favour of both protective effects of long-lasting marriage and detrimental effects of marital dissolution were found. Studies would benefit from including marital history in the models instead of baseline marital status whenever possible, especially when studying male mortality.