The aim of the study was to evaluate the mast cell-blood vessel relationship using double staining CD34/AAS. Sections from 14 cases with lip tumors have been stained with Hematoxylin-Eosin. On additional sections from each case, we highlighted blood vessels by immunohistochemistry for CD34 antigen using the method LSAB2-HRP/DAB, followed by alcian blue-safranin stain for mast cells. We quantified the density, distribution and the mast cell types as well as the correlation with the number of blood vessels. All cases have been positive for both staining. We observed a significant correlation between the number of vessels and the mast cells (p = 0.003). In one case, we observed the mast cells stained with safranin (red), the vascular density being less than the mast cells density. Our results confirmed the data from the literature with respect to the large number of mast cells observed in the malignant tumors. The increased vascular density together with the mast cell density suggests a correlation between these two elements in the tumor angiogenesis, possibly though the VEGF secretion. The CD34/AAS stain is a quick and simple method and it allows an optimal correlation between the number of mast cells and blood vessels on the same section. The type of mast cells correlated with microvessel density is a powerful argument towards the involvement of the mast cells in the tumor angiogenesis of the malignances of the lips.