Video-assisted thoracic surgery (VATS) has been advocated as one of the primary diagnostic modalities for suspicious pulmonary nodules and diffuse interstitial lung disease. The aim of our study was to evaluate the cost and safety of VATS lung wedge resection(s) as an "overnight" hospital admission. We retrospectively reviewed all 37 charts of patients who underwent VATS wedge resections for these indications from August 1999 to April 2001. There was a slight female predominance with mean age of 56.8 years (range 33-88). Eighteen patients had interstitial disease and 19 patients had pulmonary nodules. The duration of chest tube drainage was one day in the majority (92%). Length of hospital admission was overnight in 70 per cent whereas 22 per cent remained two days. This latter group from the earlier period of the trial had characteristics identical to those of an overnight stay. This creates a potential overnight stay in 87 per cent. Five complications occurred in three patients, which extended the length of stay. No mortality was reported. The overall hospital charges for the overnight-stay VATS were nearly half the charges for the open thoracotomy counterpart. Diagnostic VATS wedge biopsy is a cost effective and safe procedure allowing an overnight hospital stay in the majority of cases.