Videothoracoscopy has been proven to be a safe tool to establish the diagnosis in .90% of patients with exudative pleural effusions of unknown origin. In the majority of patients with malignant pleural diseases, the endoscopic appearance of pleural lesions during white light thoracoscopy is suggestive of malignancy, but could be misleading in some cases. The aim of the present study was to estimate whether the combination of thoracoscopy with autofluorescence modalities would be useful to further improve the diagnostic accuracy of the conventional method.The present study displays early results of thoracoscopy performed consecutively with a normal light source and with autofluorescence light in 24 patients with exudative pleural effusion during 2003-2004. In all cases of malignant pleuritis (carcinoma or mesothelioma), the colour of the affected area of the pleura changed from white/pink to red (sensitivity 100%). However, in two cases of chronic pleuritis, a colour change from white/pink to orange/red was recorded (specificity 75%).In conclusion, the calculated positive predictive value of colour change for malignant pleuritis during autofluorescence thoracoscopy in this study was 92%. However, the clinical value of autofluorescence thoracoscopy in daily practice remains to be proven.