Abstract: Objective: To investigate the relationship between fluorodeoxyglucose(FDG) uptake and the clinical stages of adeno-carcinoma(AC) and squamous cell carcinoma(SCC) in the lung. Methods: We reviewed the data from 94 cases of AC and 65 cases of SCC who underwent FDG PET/CT in the nuclear medicine center of our hospital between June 2004 and April2007. The differences in FDG uptake and tumor size between AC and SCC were evaluated. The correlation between SU-Vmax and tumor size or clinical stage was also analyzed. Results: Tumor size and SUVmax were significantly higher in SCC patients than in AC patients. (P=0.004 and P=0.012, respectively). There was a positive correlation between SUVmax and tumor size in both types of patients(P<0.001). Significant differences were found in SUVmax among different stages of AC(P=0.000). A significant correlation was found between tumor stage and FDG uptake value for AC patients (r=0.420, P=0.000). Conclusion: FDG uptake of AC and SCC tumors in the lung are influenced by histologic subtype. SUVmax of AC is correlated with stage.