CD44 is an integral membrane glycoprotein, functioning as the receptor for hyaluronic acid. CD44 is expressed on epithelial, mesenchymal, lymphoid, and glial cells. CD44 distribution, pattern of staining, and isoform types are altered in neoplastic conditions, including cervical dysplasia and carcinoma. We have studied CD44 expression by immunohistochemistry in 49 patients with cervical intraepithelial neoplasia (CIN) I, II, III invasive squamous cell carcinoma of the uterine cervix and controls. Only membranous staining was considered positive. Diffuse membranous staining was observed in all controls and CIN I cases, but only in 7/10, 3/10, and 4/9 cases of CIN II, CIN III and squamous cell carcinoma, respectively. The remaining cases showed either complete lack of staining, only focal membranous staining or only diffuse inconsistent (weak/cytoplasmic/fragmented) staining. Three invasive carcinomas showed both areas of membranous staining and areas of inconsistent staining in the same section. No correlation was observed between tumor grade and CD44 pattern of staining. Human papillomavirus (HPV) was found in 24/29 high-grade intraepithelial lesions and carcinomas. HPV expression did not correlate with CD44 staining. In conclusion, CD44 expression was found to be reduced in more than 50% of high-grade intraepithelial neoplastic lesions and invasive carcinomas. This might be associated with the loss of cellular adhesion characteristics of pre-invasive and invasive lesions. HPV presence did not seem to influence CD44 expression.