The objective of the study was to compare cyclooxygenase-2 (COX-2) expression in cervical intraepithelial neoplasia III (CIN III) and squamous cell carcinoma (SCC) of the cervix, and its correlation with clinicopathologic factors of SCC with a review of the available literature. This study included 25 patients with CIN III and 67 patients with stage I-IIa SCC. All patients in the SCC group were treated with radical hysterectomy plus pelvic and para-aortic lymphadenectomy and postoperative chemoradiotherapy based on their histopathologic risk factors. Immunohistochemical analysis was performed on paraffin-embedded sections with COX-2 antibody. COX-2 expression in the SCC group was significantly higher than in the CIN III group (55.2% [37/67] vs 24% [6/25]; P = 0.008). Significantly higher expression of COX-2 was observed in patients with lymphovascular space invasion (LVSI) compared to patients without LVSI (61.9% [34/55] vs 33.3% [3/9]; P = 0.02). Additionally, patients with tumor sizes > 4 cm had significantly higher COX-2 expression than patients with tumor sizes < 4 cm (65.9% [27/41] vs 39% [10/26] P = 0.028). There was no significant relationship with respect to COX-2 expression and parametrial involvement, lymph node metastasis, recurrences, and survival. In multivariate analysis, LVSI was the only statistically significant determinant for COX-2 expression (P = 0.024; OR = 2.35; 95% CI = 1.1-4.9). Our results and a review of the literature both suggest that COX-2 expression may have a role in the development and progression of CIN III and it is related to some clinicopathologic variables of cervical carcinoma. Further studies are needed to clarify the role of COX-2 inhibitors in the management of CIN and SCC.