OBJECTIVE: To evaluate the diagnostic accuracy of transthoracic trucut biopsy needle wash cytology in the diagnosis of lung neoplasms. STUDY DESIGN: Thirty-one cases that had clinical and radiological evidence suggestive of peripheral lung tumors were studied. Trucut biopsy was done under radiological guidance in all of the cases, and 2 to 3 touch imprint smears were made before the biopsy tissue was sent for histopathology. The trucut biopsy needle was washed in normal saline for rinse fluid cytology. RESULTS: Of the 31 cases studied, 30 cases were diagnosed with lung malignancy on histopathology. A positive result was given by rinse fluid cytology in 23 (76.67%) cases. The sensitivity of rinse fluid cytology was 76.67%, specificity was 100%, positive predictive value was 100%, negative predictive value was 12.5%, and efficacy was 77.42%. A positive result was given by imprint cytology in 27 (90.00%) cases. The sensitivity of imprint smear cytology was 90%, specificity was 100%, positive predictive value was 100%, negative predictive value was 25%, and efficacy was 90.32%. There were no false positive cases. CONCLUSION: The diagnostic utility of rinse fluid and imprint cytology is significant and can be of great help in the diagnosis of tiny bronchoscopic or endoscopic biopsies, where low yield of diagnostic material is always a problem. © Science Printers and Publishers, Inc.