Background and objective It has been proven that lung cancer in the youth exhibited rapid progres-sion, thus timely and accurate diagnosis is crucial. hTe aim of this study is to explore the clinicopathological characteristics of lung cancer in the youth, so as to provide clues for diagnosis. Methods hTe study enrolled patients aged younger than 40 years with lung cancer diagnosed with histology or cytology in our hospital between 1995-2012. We retrospectively analyzed sex, age, symptoms, smoking history, histology, stage and misdiagnosis. Results One hundred and thirty patients with lung cancer in the youth were enrolled, which comprise 5.2%of all cases of lung cancer in that period. Among them, 68.5%were male;53.8%were aged between 36 and 40 years. Common symptoms included cough and hemoptysis, and systematic symptoms were relatively uncommon;and 11.8%showed no symptoms. 63.3%had a smoking history, and the time between initial symp-tom and ifnal diagnosis averaged 3.9 months. hTe misdiagnosis rate was 51.5%, with tuberculosis as the leading misdiagnosis. 85.4%were staged III/IV. Primary lesion otfen located in upper lobes. Adenocarcinoma was the commonest histology, and 72.3%of the whole group was poorly differentiated. Conclusion Lung cancer in the youth showed some special clinicopatho-logical characteristics. Doctors should consider the possibility of lung cancer in patients with seemly diagnosis of tuberculosis, especially in those without symptomatic symptoms, and perform histological or cytological examinations. The absence of smoking history cannot rule out the possibility of lung cancer in youth patients.