We analyzed our experience with 42 consecutive patients who had pleural effusions (seven benign exudates, 12 malignant exudates, and 15 empyemas) or pneumothoraxes (eight patients) treated over a 3-year period by catheters placed percutaneously under imaging guidance. The catheters ranged in size from 8 French to 14 French. Although the overall success rate was 71% (30/42), the success rate during the first 2 years was 57% (12/21), compared with 86% (18/21) during the third year. The success rates according to collection type were 63% (12/19) for exudates, 80% (12/15) for empyemas, and 75% (6/8) for pneumothoraxes. There were two complications: a vasovagal reaction and a sterile collection converted to an empyema. After an initial learning period and with accumulated experience, radiologically placed catheters have proved to be an efficacious treatment of pleural effusions and pneumothoraxes that has a low complication rate.