Epidermal growth factor receptor (EGFR) is overexpressed in a variety of malignancies, including breast, lung, gastric, and cervical carcinoma. Its overexpression has been associated with disease progression or poor prognosis in patients with cervical carcinoma. In the present study, the levels of EGFR were determined in serum from 38 patients with cervical carcinoma [invasive or recurrent carcinoma (n = 26) and carcinoma in situ (CIS; n = 12)] and 38 healthy female controls using ELISA. The mean serum level for EGFR in patients with invasive or recurrent carcinoma (165 +/- 60 fmol/ml) was significantly elevated (P < 0.0001) compared with that of healthy controls (66 +/- 17 fmol/ml) and also higher (P = 0.015) than that of patients with CIS (126 +/- 25 fmol/ml). In addition, there was a significant difference in the mean serum levels of EGFR between patients with CIS and healthy controls (P < 0.0001). Thirty-five patients (92%) with cervical carcinoma [invasive or recurrent (n = 24) and CIS (n = 11)] had elevated serum, EGFR levels above the cutoff value of 100 fmol/ml (defined as 2 SD above the mean of the controls). In conclusion, the serum EGFR level was elevated in a significant proportion of patients with cervical carcinoma, and it demonstrated an increasing tendency according to disease progression from normal tissue through CIS to invasive cervical carcinoma. Therefore, it may have a potential usefulness as a biological marker of cervical carcinoma.