This uncommon non-small cell variant of lung cancer is characterized by combined histopathologic features of squamous cell carcinoma and adenocarcinoma. Most patients have history of smoking and the clinical presentation is similar to that of other non-small cell carcinomas. A requirement for diagnosis is that each component represents at least 10% of the tumor substance. Furthermore, unequivocal evidence of squamous lineage consisting of squamous pearls, or cells with intercellular bridges plus unequivocal evidence of glandular differentiation consisting of acini, tubules, or papillary formations are required for definitive diagnosis. These tumors are almost always peripherally located and rarely accessible to the bronchoscope. High-grade mucoepidermoid carcinomas (MEC) must be differentiated from adenosquamous carcinomas. A helpful distinguishing feature of MEC is their central location.