Abstract:To assess the place of bronchoscopy in the investigation of pleural effusion, 245 patients presenting during a two year period were reviewed. Of the 46 patients who had bronchoscopy, a positive yield was obtained in 13, though in five of these a second pleural aspiration was also diagnostic. Bronchoscopy was more likely to be diagnostic in patients presenting with a cough (12/24) than in those with no cough (1/22) (p<0.001), and in those whose chest X‐ray revealed significant radiological abnormalities such as hilar enlargement, lung mass or persisting consolidation (12/29), than in those without such changes (1/17) (p<0.01).Bronchoscopy has a limited role in the investigation of pleural efision. The presence or absence of cough, and the appearance of the chest X‐ray, are both important considerations when planning the investigation of an undiagnosed pleural effusion. (Aust NZ J Med 1992; 22: 41