Mutations of the tumour suppressor gene p53 are common in human cancer, and seem to be an early event in head and neck squamous cell carcinomas. The aim of our study was to determine the status of the tumour suppressor gene p53 in the oral mucosa of patients previously treated for a head and neck squamous cell carcinoma, at risk of developing an oral squamous cell carcinoma, but without oral clinical lesions. Oral brushings from 87 patients were sequenced with matched genomic DNA. No mutations were found in exons 5, 7 and 8, whereas in exon 6 silent mutations (n=6) and a polymorphism (n=7) were found. Mutation of the tumour suppressor gene p53 does not seem to be a frequent event in patients at risk but without oral lesions.