RESULTS: One hundred fifty-one patients were included in the study, with a mean age of 65 ± 14 years. The overall diagnostic yield was 58.3%. Sensitivity was 43.2% in malignant disease and 78.1% in benign disease. The etiology of lung lesion (P = < 0.001), lesion size (P = 0.018) and the presence of bronchus sign (P < 0.001) were factors influencing the yield of flexible bronchoscopy by univariate analysis. In multivariate logistic regression analysis, the exposed type of bronchus sign and benign lung lesions were determinant factors (OR 22.4, 95% CI 6.5-77.7, P < 0.001; OR 6.4, 95% CI 2.5-16.1, P < 0.001).