Summary Life expectancy of Swedish haemophiliacs has been estimated for the period 1831–1980. The data were derived from 948 haemophiliacs of whom 580 survived throughout 1980. Applying standard demographic techniques, median life expectancy of patients with severe haemophilia was found to have increased fivefold, from a mere 11 years during the period 1831–1920 to 56.8 years during 1961–80. The corresponding estimates for patients with moderate haemophilia were 27.5 and 71.5 years, respectively. The limited data on patients with mild haemophilia did not indicate any significant improvements in mortality. From the beginning of this century to 1980 median life expectancy for Swedish males increased from 61.7 years to 75.6 years, an increase of 23%. Analysing the last 12 years of the study (1969–80), death rates for patients with severe haemophilia below the age of 45 were not much different from those of Swedish males in the population as a whole. The investigation implies that the mortality of haemophiliacs in Sweden is approaching that of the total male population.