Background: To determine the potential clinical utility of tumor markers CEA, TPA, and SCC-Ag for early detection of cervical precancerous lesions. Materials and Methods: A case-control study was carried out on 120 women (46 patients with histologically confirmed cervical precancerous lesions and 74 healthy controls). The significance of serum selected tumor markers in early detection of cervical intraepithelial neoplasia (CIN) were assessed. Results: Of the case group, the rates of CIN I, II, III, was 69.6%, 23.9%, and 6.5%, respectively. According to the manufacturer's cut-off values of 2ng/ml, 5ng/ml, and 70 U/ml for SCC-Ag, CEA and TPA tests, in that order, SCC-Ag test had a sensitivity of 13%, but CEA and TPA tests could not distinguish between case and control groups. The diagnostic sensitivities were highest at cut-off values of 0.55 ng/ml for SCC-Ag, 2.6ng/ ml for CEA, and 25.5 U/ml for TPA which were 93%, 61%, and 50%, respectively. However, the area under the receiver operating characteristic curve was the largest for SCC-Ag (0.95 vs. 0.61 and 0.60 for CEA and TPA, respectively). Moreover, there was a highly significant direct correlation between SCC-Ag concentration and the degree of cervical precancerous lesions (r=0.847, p<0.001). Conclusions: The new cutoff of 0.5 for SCC-Ag test might be useful as a tumor marker in Iranian patients with CIN and it needs to be more evaluated by studies with larger populationa.