We conducted a computed tomography (CT) screening for lung cancer in a high-risk population. Six hundred and two workers (38-81 years, 97% smokers) with asbestos-related occupational disease were screened using spiral CT and chest radiography. The national cancer registry was checked for possible false negative cases. The screening detected 111 patients with non-calcified nodules >0.5 cm in diameter and 66 of them were referred for further hospital examination. We found five lung cancers (106 false positive cases) with a histological spectrum similar to the national, natural occurrence of the disease (two adeno, one squamous cell, one anaplastic and one metastatic carcinoma) and one peritoneal mesothelioma. Three cases were potentially operable (stage I-II). Unfortunately there was one false negative fine-needle aspiration biopsy (FNAB) with misinterpretation of the follow-up CT scan and another patient who refused further investigations after an inadequate FNAB. In the end only one patient with adenocarcinoma underwent surgery. After 3 years of follow-up two new lung cancers were reported to the cancer registry with no evidence of tumour in the retrospective analysis of the screening CT scan. The sensitivity of CT screening was 100%. CT was capable of detecting early lung cancer in asbestos-exposed patients with a lot of confusing pulmonary and pleural pathology. Due to the high number of positive findings attention should be paid to patient compliance and the follow-up protocols and patient selection in future screening programmes.