High-resolution computed tomography (HRCT) has been shown to accurately visualise parenchymal infiltrates of sarcoidosis. The aim of this study was to compare the diagnostic yield (DY) of HRCT with that of endobronchial (EBB) and transbronchial (TBB) biopsies in establishing the diagnosis of sarcoidosis. Forty-five patients referred to Helsinki University Central Hospital with a presumptive diagnosis of sarcoidosis underwent fiberoptic bronchoscopy (FOB) with bronchoalveolar lavage (BAL), EBB, TBB and HRCT. Thirty-seven of the patients were diagnosed as having sarcoidosis, 34 of whom showed a parenchymal infiltrate in HRCT. One of the three patients with no parenchymal findings, had positive findings in TBB, and all had lymphocytosis in BAL. The DY for sarcoidosis by EBB and TBB was 24.3% and 50.0%, respectively. The addition of EBB to TBB improved the DY by 8.3%, whereas adding TBB to EBB improved the DY by 30.6%. There were no major complications after the FOB, which was always performed under fluoroscopic control. In conclusion, HRCT is a valuable tool in diagnosing sarcoidosis. However, the HRCT findings cannot be seen in all patients with positive findings in lung biopsy, nor is the parenchymal infiltrate specific for sarcoidosis. Attempting biopsy-proven diagnosis of sarcoidosis is still recommended. Fiberoptic bronchoscopy with EBB and TBB under fluoroscopic control is a safe and well-tolerated procedure.