CT bronchus sign (BS) designates a bronchus leading directly to a peripheral pulmonary lesion. The objective of this investigation is to determine the contribution of BS-guided bronchoscopic multiple diagnostic procedures (BMDPs) to the diagnostic yield of solitary nodules or masses (SPNMs) suspected of pulmonary carcinoma (PC). A prospective study was carried out in 92 patients with a 2-5 cm diameter SPNM at the level of third to fifth bronchial branching and without endobronchial tumors. Within 10 days after 2-mm CT scans were done, in each of 92, bronchial washing (BW), brushing (BR), transbronchial needle aspiration (TBNA) and transbronchial lung biopsy (TBB) were performed respectively, via fiberoptic bronchoscopy (FB) under fluoroscopic guidance. In 40 (82%) of 49 with BS and in 19 (44%) of 43 without BS, FB established the diagnosis (p < 0.01). In 84 cases of PC, BW, BR, TBNA and TBB provided the diagnostic yields of 4% (3), 26% (22), 57% (48) and 49% (41), respectively; the combined yield reached 68% (57). A metastasis and a tuberculoma were diagnosed exclusively by TBB, and TBNA, respectively. All differences of diagnostic yield except that between TBNA and TBB (p > 0.05) were determined to be significant (p < 0.05). Thoracotomy verified diagnosis in 48 of 59 cases diagnosed and 19 of 33 undiagnosed by FB, and various tissue biopsies or clinical follow-up in 11 diagnosed and 14 undiagnosed by FB. The above data suggest that in the diagnosis of PC as a SPNM at the level of third-fifth bronchial branching, combining the guidance of CT BS, and BMDPs under fluoroscopic guidance can increase the yield considerably.