The influence of preoperative examination of oral squamous cell carcinoma (OSCC) mucosal surrounding by VELscope (Visually Enhanced Lesion Scope) on the radicality of surgical treatment of OSCC was the goal of this study.It is the first analysis of its kind with a total number of 122 patients suffering from OSCC with homogenous distribution of different tumor stages randomized into a study and a control group and enrolled in our study after meeting the inclusion criteria. The preoperative checkup by VELscope accompanied by the marking of the range of a loss of fluorescence in the study group was performed before the surgery. We have developed a unique mucosal tattoo marking technique for this purpose. The pathohistological results after surgical treatment, i.e. the margin status, were then compared. We achieved the pathological free margin (pFM) in 55 patients, the pathological close margin (pCM) in 6 cases and we encountered no case of the pathological positive margin (pPM) in the mucosal layer in the study group. In comparison, the control group results revealed pPM in 7 cases, pCM in 14 cases and pFM in 40 of all cases in the mucosal layer. This study proved that the preoperative autofluorescence evaluation of a tumor mucosal surrounding can enhance the ability to reach the pFM resection.