Abstract: Introduction- Primary lung epithelial malignancies are the most common neoplasms among all lung masses. Lung carcinoma is the leading cause of death for which a histological or cytological confirmation and categorization of malignancy is required before treatment. It is desirable to have both FNAC or TBNA and biopsy for exact diagnosis. Sometimes, even immunohistochemistry is required to confirm the diagnosis. Materials and method- Total 110 patients from the chest medicine department, having lung mass in CT scan findings, going for CT guided FNAC or trans bronchial needle aspiration and true cut biopsy or bronchial biopsy in the pathology department, are included in this prospective study. IHCs are done in some cases for exact categorization of the tumour. SPSS software is used for statistical analysis. Result- Out of 110 patients, 80 patients (72.73%) are male and 30 (27.27%) are female and most of them (37.27%) are in 7th decade. Among these, 42 patients (38.18%) are diagnosed to have primary lung adenocarcinoma and 38 patients (34.55%) have primary squamous cell carcinoma of lung and 13 patients (11.82%) have secondary metastatic deposit in lung from different primary malignancies. Sensitivity and specificity of cytology to diagnose primary lung mass are 76.92% and 77.78% respectively and sensitivity of cytology for secondary lung mass is 92.31%. Sensitivity of histopathology for diagnosing primary lung tumour is 92.78%. Cohen’s Kappa shows Kappa is 0.741 i.e. there is a good strength of agreement between the procedures. The P value < 0.0005 indicates that the Kappa co-efficient is statistically significantly different from zero. Conclusion- Most of the lung masses are diagnosed properly by cytological and histopathological examination. But some cases, immunohistochemistry is required to confirm the diagnosis because diagnosis of non- small cell carcinoma or poorly differentiated carcinoma is not helpful for specific therapy.