The p53 suppressor gene is the most frequently altered gene in solid human malignancies. It is located on the short arm of chromosome 17 in the region 17p13 and encodes a 53kD nuclear phosphoprotein containing 393 amino acids with specific DNA binding properties and a short life span. The wild p53 protein has been classified as a tumoral suppression gene with a determining role in controlling cellular proliferation and differentiation and can be inactivated through mutation in the protein sequence encoding the gene, leading to neoplastic transformation. In this study we analyzed the expression of p53 protein in a variety of salivary gland malignant tumors fixed in formalin and included in paraffin, using the method of immunohistochemical coloring with the anti-p53 DO-7 antibody. The evaluation of the immunoreactivity with p53 proved a significantly more intense coloring in salivary gland high-grade malignant tumors and the observed immunomarking of over 50% of the tumoral cells is correlated with the weak differentiation of the tumors, giving a predictive factor for the evolution of the disease.