Mutated p53 proteins accumulate in the nuclei of tumor cells, and anti-p53 autoantibodies are found in the sera of patients with non-small-cell lung carcinoma (NSCLC). We analyzed the correlation among serum anti-p53 autoantibodies, immunohistochemical staining for p53, and clinical features (age, gender, smoking history, histological type, differentiation, stage, T factor, tumor size, and N factor) in resected non-small-cell lung carcinomas. A total of 62 cases of resected NSCLC were studied (43 men and 19 women; 33 adenocarcinomas, 21 squamous cell carcinomas, 8 large-cell carcinomas). Preoperative serum titers of anti-p53 autoantibodies were detected in 13/62 cases (21.0%). A correlation between histological type and positive titers of serum p53 autoantibodies was seen (large-cell carcinoma versus squamous cell carcinoma and adenocarcinoma, P = 0.031, chi2-test). Out of 25 cases, 10 (40%) with positive immunohistochemical staining for p53 had positive titers, whereas 3 positive titers were found in 37 patients with negative immunohistochemical staining for p53 (P = 0.0025, chi2-test). Serum titers of anti-p53 autoantibodies were present in approximately 20% of the cases of NSCLC, and overexpression of p53 protein in tumor cells was detectable in approximately 40%. Serum anti-p53 autoantibodies may be a clinical parameter for the presence of p53 mutations and p53 overexpression in NSCLC patients.