The inactivation of the tumor suppressor gene p53 has been demonstrated in a variety of human tumors. In this study, we present a p53 gene analysis of 13 uterine carcinoma cell lines. Sequencing analysis of the entire coding region revealed mutations changing the p53 amino acid composition in all six endometrial carcinoma cell lines tested (Ishikawa, Hecl-A, Hecl-B, KLE, RL95-2, and AN-3). Of the seven cervical carcinoma cell lines, two (HT-3 and C-33A) contained p53 codon changes as well. We were unable to detect human papillomavirus in these two cell lines. By contrast, five human papillomavirus-positive cervical carcinoma cell lines (HeLa S-3, Caski, SiHa, C-4I, and ME-180) contained wild-type p53 gene sequences. We suggest that, in the human papillomavirus-positive cervical tumors, p53 inactivation occurred via the known mechanism of viral E6/cellular p53 protein association, whereas in all other tumors p53 function was compromised by changes in the amino acid sequence.