We had reported the utility of virtual bronchoscopic navigation system under CT-guidance for the diagnosis of small peripheral pulmonary lesions (PPLs). This study investigated the efficacy of virtual bronchoscopic navigation system for the diagnosis of small PPLs under X-ray fluoroscopy. We performed bronchoscopy with this system for 94 consecutive patients with 96 PPLs (< or =30mm in longest diameter; mean longest diameter, 16.2mm). A standard bronchoscope was used in 38 cases, and an ultrathin bronchoscope in 58 cases. Virtual bronchoscopic images were reconstructed from helical CT data. All the examinations were performed under X-ray fluoroscopy with virtual bronchoscopic navigation system, we referred both virtual bronchoscopic images and actual bronchoscopic images simultaneously to navigate the bronchoscopic pathway to the PPLs. Specimens for pathological examination were collected by transbronchial biopsy (TBB) and/or brushing. Virtual images accorded well with actual bronchoscopic images. The average total examination time was 24.1+/-7.4min (mean+/-S.D.). The overall diagnostic yields were 62.5% (60 of 96 PPLs), 71.1% (27 of 38 PPLs) with the standard bronchoscope, and 56.9% (33 of 58 PPLs) with the ultrathin bronchoscope. Diagnostic rates were 35%, 61.4% and 94.7% for lesions < or =10, 10-20, and >20mm, respectively. There were eight ground glass opacity (GGO) lesions confirmed only on CT scans; seven cases were pathologically diagnosed. All the examinations were performed safely with no complications. Bronchoscopy with virtual bronchoscopic navigation under X-ray fluoroscopy is useful for the diagnosis of small PPLs.