We report our experience with the use of video-assisted thoracoscopic surgery [VATS] in the diagnosis of intrathoracic disease of unknown origin. In the last two years, 32 patients (18 males) underwent this procedure for diagnostic purposes. Of them, 18 patients had lung pathology, eight mediastinal and six pleural disease. All attempts at achieving a tissue diagnosis were unrewarding. In all of them, diagnostic thoracotomy was being contemplated to procure tissue for histopathological diagnosis. Diagnostic thoracoscopy was successful in providing tissue diagnosis in all the patients with lung disease; seven of the eight patients with mediastinal pathology and five of the six patients with pleural lesions. Diagnostic thoracoscopy was associated with minimal morbidity, short hospital stay, better cosmetic result and quicker return to work as compared to conventional thoracotomy. We conclude that video-assisted thoracoscopy is an excellent diagnostic tool to confirm tissue diagnosis in patients with undiagnosed chest diseases.