Background: Pleural Effusion (PE) is a sign of disease and not a diagnosis itself. Hence an attempt was made to find out the etiological diagnosis of pleural effusion in cases.Methods: Single center, observational, cross sectional hospital-based study. Samples were collected by systematic random sampling method; study was conducted in GSL Medical College. Patients admitted with pleural effusion in medical wards and ICU were taken. The patients >14 years age, both genders were included. All patients were interviewed to obtain detailed history and examined thoroughly as per pre-determined protocol. Chest x-ray, chest ultrasonogram, PF analysis, routine general investigations were conducted for all the participants; and pleural cytology in certain cases. PF was aspirated send for various microbiological investigations such as gram stain, culture.Results: Out of 104 study participants, 78 were men and 26 were women and peak incidence of pleural effusion is 41-50 years. In this study, 58% cases were found to be tuberculoid, 25% malignant, 6% pyogenic.Conclusions: Tuberculosis was found to be commonest and more prevalent cause of pleural effusion. Every case of pleural effusion should be meticulously investigated in order to arrive a diagnosis, whether tuberculous or non-tuberculous to proceed for specific therapy.