Our objective was to estimate the excess mortality and the reduction in life expectancy related to diabetes mellitus. We developed a life table to describe the Dutch population in two states, diabetic and non-diabetic, using age- and sex-specific prevalence of diabetes mellitus and risks of dying for diabetic subjects. We compared the calculated excess deaths with registered deaths. The cause-of-death registration practice underestimates diabetes-related mortality. The method used in this study, combining mortality data with data from epidemiologic studies, provides an assessment of the impact of diabetes on the Dutch population.