Pleomorphic carcinoma (PC) of the lung is rare, and it is classified as a subtype of sarcomatoid carcinoma of the lung in the World Health Organization histologic classification of lung tumors. In this study, 70 cases of PC surgically resected were reviewed to identify its clinicopathologic characteristics. There were 57 men and 13 women, and their mean age was 66 years (range: 29 to 80 y). Sixty-eight tumors contained identifiable epithelial components, and the other 2 consisted of spindle cells and giant cells alone. An adenocarcinoma component was found in 34 cases, a squamous cell carcinoma component in 13, and a large cell carcinoma component in 40. The overall survival rate and disease-free survival rate were 36.6% and 40.7%, respectively, and both rates were significantly lower than for other nonsmall cell lung carcinomas. When the PC patients were divided into 3 groups according to the predominant epithelial component, an adenocarcinoma group, squamous cell carcinoma group, and large cell carcinoma group, there were no significant differences in the overall survival rate and median survival time between the 3 groups. Univariate analysis revealed that advanced stage (stage III), mediastinal lymph node metastasis, lymphatic permeation, and histologically diagnosed massive coagulation necrosis (>25% of the tumor) predicted poorer disease-free survival. Multivariate analysis showed that massive necrosis alone was an independent prognostic factor. We concluded that PC should be considered as an aggressive disease and massive necrosis should be routinely reported and used as a factor in clinical assessments.