Basaloid carcinoma of the lung is a rare primary neoplasm, first described in 1992. Basaloid carcinoma is an aggressive subtype of Non small cell lung cancer, with poor 5-year survival, even in stage I and II resected tumors. Differential diagnosis from small cell, Neuroendocrine large cell and poorly differentiated squamous cell carcinoma is difficult to be made. We report a patient with lung basaloid carcinoma, initially diagnosed and treated as small cell carcinoma. Thoracotomy and resection of the tumor following chemotherapy, established the correct diagnosis.