Objective: Precise subclassification of lung cancer, mostly performed in biopsy or fine needle-aspiration specimens, is required for appropriate therapy. Moreover, distinction between primary and metastatic carcinoma is critical. Thus, the role of immunohistochemistry (IHC) has been emphasized, although an optimal IHC diagnostic algorithm has not been firmly established. Herein, we evaluated the performance of the IHC panel used at our institution in subclassification of lung cancer and identification of metastatic carcinoma. Method: Cases of non-neuroendocrine lung carcinoma, diagnosed from March 2011 to April 2012 were selected. IHC was performed for CK7, CK20, TTF-1 and p63. Resection specimens were compared with the respective biopsy. Results: Of 184 cases analysed, 73 (39.7 %) were diagnosed as lung adenocarcinoma, 59 (32.1 %) as epidermoid carcinoma, 22 (12 %) as other forms of NSCLC, and 17 (9.2 %) as metastasis. Importantly, 26 % of primary lung adenocarcinomas were initially suspected to be metastasis. In 26 cases submitted to surgical resection, 22 (84.6 %) were correctly diagnosed in the biopsy, revealing a substantial agreement (κ-value=0,757). Conclusion: Our IHC panel allows for reliable subclassification of lung carcinomas in most cases and is decisive for appropriate diagnosis in patients suspected of lung metastasis, which is critical issue in a cancer institute.