RATIONALE: EBUS-TBNA has become an effective way of tissue assessment, but the small sample volume can be problematic. Identifying molecular mutations is a key to personalized treatment. This is the first study evaluated the efficacy of EBUS-MFB added on EBUS-TBNA to improve the tissue adequacy and the overall diagnostic yield. METHODS: Prospective study, patients with enlarged intrathoracic lymph nodes underwent EBUS-TBNA followed by EBUS-MFB. The tissue adequacy for molecular analysis required that the tissue samples met both a tumor cell count of more than 100 cells and an NCP estimation of more than 25%. RESULTS: Twenty-one of fifty-seven nodes were diagnosed with malignant disease by both techniques. The tissue adequacy of EBUS-TBNA was 90.5% comparable to EBUS-MFB added on EBUS-TBNA, which was 95.2% with no statistical significance (p=0.317). EBUS-TBNA resulted in higher tumor cell counts (>1,000 cells) were 80.9% compared to EBUS-MFB 47.6% (p=0.039). The EBUS-MFB added on EBUS-TBNA significantly improved the overall diagnostic yield compared to EBUS-TBNA alone (98.2% vs 87.7%; p=0.031), including three anthracotic lymph node, two granulomatous nodes, and one silicotic node. No serious adverse events were observed, only 2 patients out of 52 (3.84%) had minor bleeding. CONCLUSION: The tissue adequacy for molecular analysis by EBUS-TBNA and EBUS-MFB added on EBUS-TBNA were not different. However, EBUS-TBNA showed better tumor cell counts and more suitable. Also, the EBUS-MFB added on EBUS-TBNA is a feasible and safe procedure which may provide more diagnostic yield.