To improve the efficacy of fibreoptic bronchoscopy in the diagnosis of peripheral lung cancer, we evaluated the effectiveness of various techniques for obtaining samples for cytological examination. Between January 1984 and December 2000, flexible fibreoptic bronchoscopy under fluoroscopic guidance was performed in 1372 patients with lung cancer having no visible endoscopic findings. Histological examination of specimens obtained by forceps biopsy and cytological examinations on imprints of biopsy specimens, brushing, selective bronchial lavage, curettage, transbronchial needle aspiration, rinse fluids of the forceps, brush, curette, and aspiration needle, and all fluids aspirated during the bronchoscopic examinations were evaluated for diagnostic power. Using these techniques, the overall diagnostic rate with bronchoscopy was 93.4%. The sensitivity of the histological examination was 76.9%; additional imprint cytology increased the sensitivity to 84.8% (P<0.0001), while additional cytology on the rinse fluid of the forceps increased the sensitivity to 83.7% (P<0.0001). The addition of both imprint cytology and cytology on the rinse fluid of the forceps increased the diagnostic rate to 86.2% (P<0.0001). Our results indicate that cytological examinations of the imprints of biopsy samples and the rinse fluids of the forceps and the brush improve the efficacy of fibreoptic bronchoscopy in the diagnosis of peripheral lung cancer.