Twenty-one Japanese patients with sebaceous carcinoma of the eyelid were investigated for tumour incorporation of human papillomavirus (HPV) types-6, 11, 16, 18, 31, and/or 33 DNA by in situ hybridization with fluorescein isothiocyanate-labelled DNA probes, and for p53 protein accumulation by immunohistochemical analysis with an antibody to p53 protein. Thirteen tumours (61.9%), including 9 cases of multiple infections, were positive for HPV DNA. Positive signal in the nucleus was observed not only in the cancer cells, but also in the cells of surrounding normal sebaceous glands and epidermis. Positive nuclear staining of cancer cells with the antibody to p53 protein was detected in 12 cases (57.1%). p53 protein accumulation was more frequently observed in the clinically advanced cases, occasionally in association with recurrence and/or metastasis. Among the 12 p53-positive cases, 7 were also positive for the presence of HPV DNA. HPV infections exist in a high percentage of sebaceous carcinomas of the eyelid in Japan; the overexpression of p53 protein may be important in both carcinogenesis and progression.