The aim of this study was to compare two preoperative staging procedures of non-small cell lung cancer (NSCLC): one using positron emission tomography (PET) and one using conventional imaging studies. Accuracy, effects on patient management, and costs were calculated. Four hundred thirteen consecutive patients with NSCLC were prospectively examined with PET and conventional imaging studies. A simulation calculated the costs of the two strategies. The accuracy of PET for metastases was 97.5% versus 84% of conventional imaging (P < 0.001). The accuracy of PET for mediastinal staging was 97%, whereas that of computed tomography was 68% (P < 0.001). The expected number of unnecessary surgeries was 24 for the conventional strategy and 8 for the PET strategy (P= 0.007). The PET strategy was less expensive. This study shows that PET is an economical tool in NSCLC staging (even in the European economic environment), with high accuracy and important management aspects.