Introduction: As angiogenesis is closely associated with the process of carcinogenesis, it was the objective of the study to evaluate histologically quantifiable angiogenesis parameters in association with the aggressiveness and the prognosis of oral squamous cell carcinoma (OSCC). Materials and Methods: There were (1) histological preparations of 49 leukoplakia (Leu), 33 Leu with mild dysplasia (Leu-SIN 1) , 13 Leu-SIN 2 and 36 OSCCs resulting from Leu. In those, microvessel density (MVD), vessel diameter and VEGF expression were analysed to calculate the effect of angiogenesis on degeneracy tendencies. Subsequently, MVD and CD31 staining intensity were correlated in 50 OSCCs with tumour staging and prognosis with a mean follow-up of 54 months (2). Results: (1) For MVD, there were significant differences between Leu and Leu-SIN 2/OSCC (p0.05) and between Leu-SIN 1 and OSCC (p0.05). For OSCC, vessel diameters were significantly increased compared to Leu (p0.05). Expression of VEGF increased significantly gradually from Leu-SIN 1 to OSCC (p0.05). (2) Significantly higher vessel counts were seen > in T3/T4, N>0 and G3-4-OSCCs (all p0.05). Higher MVD values were significantly associated with earlier relapse and earlier metastases as well as reduced overall survival (all p0.05). Discussion: With leukoplakia as a precancerous lesion, the important role of angiongensis in gradual malignant transformation towards OSCC was demonstrated. For manifestation of OSCC, angiogenesis influences both the local and metastatic tumour growth and has a significant correlation to prognostic parameters, wherein the MVD represents a possible parameter for evaluation of prognosis. Keywords: Leukoplakia, oral squamous cell carcinoma, angiogenesis