Background: EBUS-TBNA is performed to harvest cytologic and core-biopsy specimen. Although feedback from rapid cytology tests are expected to improve diagnostic rates, the value of the routine use of rapid cytology tests has not been established. Puorpose: We evaluated the clinical relevancy of Rapid on site microscopic evaluation (ROME) of core-biopsy specimens using USB microscope. Methods: We performed ROME in 20 core-biopsy specimens after EBUS-TBNA. The core-biopsy specimens were classified to five groups under microscopic view. The first group have no visual evidence of whitish tumor islet (-). The second group have one or several tiny suspicious tumor islet (-/+). The third group have less than 5 visible tumor islets (+). The fourth group have 5-10 ten tumor islets (++), The fifth group have more than 10 tumor islets (+++). The ROME was compared with final pathologic examination. Results: Among 20 specimens, 3 (15%) specimens were classified as first group (-), 2 (10%) as second group (-/+), 5 (25%) as third group (+), 7 (35%) as fourth group (++), 3(15%) as fifth group, respectively. 100% (10/10) clinical relevancy was confirmed in the fourth, the fifth group with 90% (9/10) diagnostic rate. 70% (5/7) clinical relevancy was confirmed in third group with 57% diagnostic rate (4/7). There was no clinical relevancy(5/5) in the first group and second group with no diagnostic value (5/5). Conclusion: ROME have usefullness for predicting the diagnostic value and clinical relevancy in EBUS-core biops specimens. The further study would be warranted to suppor the usefulness of ROME.