PURPOSE: The purpose of this study was to evaluate the usefulness of combined automated gun biopsy (AGB) and fine needle aspiration (FNA) in the diagnosis of lung lesions. MATERIALS AND METHODS: Lung lesions in 102 patients were aspirated consecutively using a 21-gauge fine needle and biopsied with an 18-gauge automated gun at intervals of 3 -5 minutes. Final diagnosis was based on the findings of surgery or clinical follow-up. RESULTS: In 50 patients with malignant lesions, diagnostic accuracy was 80% with AGB and 76% with FNA, but using the combined modality, the figure was 94%. In 52 patients with benign lesions, diagnostic accuracy was 54% with AGB and 50% with FNA; using the combined modality, 69 percent accuracy was achieved. For all lesions, the diagnostic accuracy of the combined modality was thus significantly higher than that of a single method (p<.05). The complications which occurred were pneumothorax in six cases (5.9%), chest tubing in two (0.2%) and minor hemoptysis in nine (8.8%). CONCLUSION: In the diagnosis of lung lesions, the combined use of AGB and FNA is safe and can increase diag-nostic accuracy.