Cytological study of uids is an inexpensive, simple procedure and has signicant utility in diagnosing neoplastic and non neoplastic lesions. The cytological examination of uids in combination with physical examination helps identify aetiologic agents, follow the natural process of the disease and monitor the response to the treatment.Aim: To determine the diagnostic utility of serosal uid cytology and analyse the incidence of neoplastic and non neoplastic lesions using serous uid cytology.Materials and Methods: This was a descriptive cross-sectional study comprising 311 cases conducted in a tertiary care hospital.Purposive sampling was used to recruit the participants. All the patients with pleural effusions, ascites or in whom Cerebral Spinal Fluid (CSF), pericardial and synovial uids examination was indicated were included. The provisional diagnosis was obtained from case sheets, including relevant clinical information. Smears were prepared from freshly tapped specimens without adding anticoagulants and were processed by routine, conventional smear technique. The data were analysed using the SPSS version 22.0 for Windows. Numerical variables were reported as frequency and percentage. The chi-square test was used wherever necessary, and the p-value less than 0.05 were considered signicant.Results: The peritoneal uid was the most common uid collected in the present study, followed by pleural uid and CSF. The malignancy rate in the present study was 19 (10.4%) of peritoneal uid, 6 (5.9%) for pleural uid, and 2 (4.1%) for CSF. Conclusion: Adenocarcinoma was the most common malignancy found in this study, which was in concordance with the research conducted earlier, where gold standard investigations conrmed the ndings. In the peritoneal uid, most of the patients had cirrhosis and tuberculosis. In pleural uid and cerebrospinal uid, most of them had tuberculosis and chronic inammatory conditions, respectively. Previous researchers conrmed similar ndings in their studies. It is seen that malignant and benign conditions like tuberculosis can be diagnosed well with effusion cytology.