A series of 125 CT-guided thoracic punctures performed over a 20-month period is reported. The only complications were pneumothorax in 14 cases, 5 of which were drained, and 1 case of hemomediastinum. For the diagnosis of malignancy the sensitivity of the method was 82%, its specificity 100% and its effectiveness 74%. The level of sensitivity rose to 86% in the last 90 cases. This method is an additional contribution to exploration of the lungs. In trained hands it gives rise to few complications and should result in a histological diagnosis in a large number of cases.