A total of 206 patients with Marfan syndrome were ascertained throughout genetic clinics in Wales and Scotland during the period 1970-1990. There were 45 deaths representing 22% of the cohort. Mean age at death was 45.3+/-16.5 years. 50% median cumulative survival in the total cohort (n=206) was 53 years for males and 72 years for females. Multivariate analysis confirmed severity as the best independent indicator of survival. These findings and survival curves will assist in the counselling of British families and individuals with Marfan syndrome.