Overexpression of the mutant p53, derived from mutation of the p53 gene which is located on the short arm of chromosome 17 and plays a role in suppression of the tumor, has been reported in some human malignancy such as breast or colon cancer and suggested to be a prognostic factor. The authors investigated expression of p53 protein by immunohistochemical staining using anti-p53 monoclonal antibody in the paraffin embedded blocks of the 23 patients who were diagnosed as adenoid cystic carcinoma of the head and neck between 1979 and 1991, and could be followed-up. Seven (30%) out of the 23 cases showed p53 expression, and there was no significant association between p53 positivity and local recurrence (p=0.41) or distant metastasis (p=0.18).