Positron emission tomography (PET) fluorodeoxyglucose (FDG) imaging may be more accurate than computed tomography (CT) scanning for staging of lung cancer disease. In the present study, we evaluate whether whole-body PET-FDG imaging can accurately stratify lung cancer patients by stage and thus predict patient outcome. Forty-one consecutive patients underwent whole-body PET and CT scanning for preoperative staging, which was then confirmed by mediastinoscopy, thoracotomy, and/or other tests revealing distant metastases. The effect of PET on patient management was determined. PET was significantly more accurate than CT for staging of lung cancer (97.6% vs. 70.7%). One-year follow-up for survival rate and treatment response was also compared in different patient groups. PET accurately identified patients with resectable disease (Group A). Group B patients, with medically inoperable disease, and Group C patients, with unresectable advanced disease, had 100% and 53% incidence of adverse events (defined as recurrence, evidence of new disease, or death), respectively. Group A patients with resectable disease who underwent surgery showed the best patient outcome, with only 7% incidence of adverse events. In conclusion, whole-body PET can be useful in identifying a group of lung cancer patients with resectable disease most likely to benefit from surgical resection. Further studies are needed to explore whether PET can predict patient outcome of various lung cancer patients receiving different treatment regimens.