Background:Pleural effusion remains the most common manifestation of pleural pathology. Sometimes it is difficult to differentiate between tubercular and malignant pleural effusion in spite of routine biochemical and cytological examination of pleural fluid.Aims:This study aims to evaluate the role of pleural biopsy to determine the etiology of pleural effusion and to correlate it with the biochemical and cytological parameters of pleural fluid.Settings and Design:Seventy two consecutive patients of pleural effusion were selected from the out patient and indoor department of a tertiary hospital of Kolkata. It was a prospective and observational study conducted over a period of one year.Materials and Methods:Biochemical, cytological and microbiological evaluation of pleural fluid was done in all cases. Those with exudative pleural effusions underwent pleural biopsy by Abram’s needle. Subsequently, the etiology of effusion was determined.Results:Malignancy was the most common etiology, followed by tuberculosis. Pleural biopsy was done in 72 patients. Pleural tissue was obtained in 62 cases. Malignancy was diagnosed in 24, tuberculosis in 20 and non-specific inflammation in 18, on histopathological examination. Out of 20 histological proven tuberculosis cases adenosine de-aminase (ADA) was more than 70 u/l in 11 cases.Conclusions:In our study, malignancy is more common than tuberculosis, particularly in elderly. When thoracoscope is not available, pleural fluid cytology and pleural biopsy can give definite diagnosis. Pleural fluid ADA ≥ 70 u/l is almost diagnostic of tuberculosis, where pleural biopsy is not recommended.