BACKGROUND/AIM: Probe-based confocal laser endomicroscopy (pCLE) is a novel diagnostic technique that can provide real-time imaging of tissues at the cellular level. In this study, pCLE was applied to liver tumors and its diagnostic value was evaluated. PATIENTS AND METHODS: Ten patients who underwent hepatectomy for liver tumors were evaluated with pCLE from February to May 2017. Immediately after liver resection, pCLE evaluation was performed in the operating room as an ex vivo study. The newly-adopted "fluorescein-dripping method" was used for the observation. RESULTS: First, the optimal fluorescein exposure time for the surface of liver was defined in the fluorescein-dripping method. Next, the distinctive findings in the cancerous region were investigated. The characteristic appearance of irregular arrangements of concentrated cells under fluorescein dripping was observed in six of seven hepatocellular carcinoma (HCC) tumors. CONCLUSION: In all HCC specimens, discrimination of the cancerous region from normal liver was possible with pCLE.