The authors performed 308 needle aspiration biopsies of parenchymal lung masses. The patients were then placed with the puncture site down for a period of at least 1 hour or until air leakage stopped. Coughing, talking, and activity were restricted. Complications included pneumothorax, at a rate of 25.0%, and chest tube placement, at a rate of 1.6%. In a subgroup of 262 patients who required only one pleural puncture at biopsy, a pneumothorax rate of 17.9% and a chest tube placement rate of 0.4% were encountered. When compared with a similar series of 143 control patients, significant reductions in both pneumothorax rate (P = .0004) and chest tube placement rate (P = .0001) were demonstrated.