A cohort of 7887 men and 576 women employed between 1928 and 1984 at a Danish asbestos cement factory Dansk Eternit Fabrik A/S was followed up for deaths, immigrations, and incident cancer cases during 1943-90. The observed number of lung cancer cases was compared with the expected number based on incidence rates for the Danish population. Internal comparison was made with Poisson modelling. A total of 226 lung cancer cases was observed; 223 cases among men and three among women. The standardised incidence ratio (SIR) for all lung cancer cases for men was 1.7; for adenocarcinoma 2.6, squamous cell carcinoma 1.7, and anaplastic carcinoma 1.5. Among the 93 excess lung cancer cases, 36 were squamous cell carcinomas, 32 adenocarcinomas and 17 anaplastic carcinomas. During the first 25 years after the start of employment the excess risk was shared almost equally between the different histological types of lung cancer, but the risk of adenocarcinomas was clearly higher after this point.