Reduced expression of the metastasis suppressor gene nm23-H1 has been previously correlated with high tumor metastatic potential and fatal clinical outcome in several types of human carcinomas. The aim of the study was to identify the expression of nm23-H1 in a variety of premalignant and malignant cervical lesions. The study comprised 106 cervical biopsies obtained from 106 women ranging in age from 23 to 68 (median 42) years. Histologic slides stained with H&E were evaluated blindly by two pathologists and a consensus diagnosis was established for each case. In addition, immunohistochemical stain was employed and a monoclonal antibody against nm23-H1 (YLEM Rome, Italy) was used. Twenty-five of the cervical biopsies showed changes of mild dysplasia (CIN I), whereas 28 demonstrated features of moderate dysplasia (CIN II) and 28 severe dysplasia (CIN III). In 25 cases infiltrating squamous cell carcinoma was identified. Expression of nm23-H1 was evident in 9/25 (36%) CIN I, 13/28 (46%) CIN II, 22/28 (78.5%) CIN III and 17/25 (68%) infiltrating carcinoma biopsies. Statistically significant differences were observed between CIN II and CIN III (p=0.003), and CIN II and infiltrating carcinoma (p=0.002) groups. Expression of the nm23-H1 gene in premalignant and malignant cervical lesions indicates that this gene may play a substantial role in carcinogenesis and tumor progression.