A mortality study has been carried out at the London, Cardiff, or Swansea Pneumoconiosis Medical Panels between 1952 and 1976 on people certified as suffering from asbestosis. The main analysis was of 665 men, 283 of whom had died. Of the deaths, 39% were from lung cancer, 9% mesothelioma, and 20% asbestosis. The observed mortality was compared with expectation based on the death rates for England and Wales. For all causes the observed number of deaths was 2.6 times expectation and for lung cancer 9.1 times expectation. After 10 years from first certification half of the men had died compared with an expectation of one in four. The excess death rates were apparent in the first year after certification and were still operating after 10 years on those who survived until then. The main factor influencing the mortality was the clinical state of the men at the time of certification, as indicated by the percentage disability awarded; the excess lung cancer rate and the mesothelioma and asbestosis rates all increased with percentage disability. Those awarded only 10% or 20% benefit were still at risk from all the three asbestos-related causes. For a man certified at age 55 it was estimated that his life expectation would be reduced by 3, 5, 8, or 12 years according to whether his rate of disablement benefit was 10%, 20%, 30% or 40% , or 50% or more respectively.