A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed whether insertion of an intercostal chest drain prolongs the length of stay of patients undergoing lung biopsy. Altogether 210 papers were found using the reported search, of which 10 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. We conclude that where an intraoperative check reveals no air leak, chest drain should be avoided if possible in order to discharge patients earlier. Where chest drain is used following video-assisted thoracoscopic surgery lung biopsy, early removal results in reduced pain and earlier discharge. Four studies advocate early chest tube removal, allowing discharge of 95% within 24 h in one study, reduced hospital stay from 3.9+/-2.1 days to 2+/-1 days (P=0.001) in another, and a median stay of 1.2 days (range 0-7 days) in a third. Removal of chest drain within 1 h of the operation was possible in 92% of patients (one study), significantly reducing pain (P=0.03, P=0.005; two studies) and postoperative complications (P=0.01; one study) compared with conventional treatment. Five studies in which patients were managed without chest drain following intraoperative air leak checks, reduced hospital stay vs. conventional management (two studies; 2 vs. 3, P<0.001, 1 vs. 3, P<0.01) but results in no difference in complication rates (three studies: pneumothoraces requiring chest drain; 2 vs. 2, P=non-significant; 0 vs. 0; 0 vs. 0) or pain score (two studies; 0.77 vs. 0.76, P=0.894; 5 vs. 5, P=0.81).