Forty-nine women with cervical intraepithelial neoplasia (CIN) grade II were treated with systemic and/or local beta-interferon (beta-IFN) applications. The aim of the study was to compare the efficacy of different routes for the administration of beta-IFN, evaluate local and systemic beta-IFN tolerance, and determine whether disappearance of neoplastic lesions was related to the resolution of the concomitant human papillomavirus infection, The patients were randomized to receive intramuscular, intralesional or a combination of intramuscular and intralesional administration, or conventional treatment, Significant differences in the rate of lesion regression were observed between treated and untreated women, The highest frequency of complete response was observed with the therapy combining intramuscular and intralesional treatment. Keywords