Neoplastic cell growth rate and the p53 expression have been recently analysed in invasive cervical carcinoma. Samples of 20 specimens with normal cervical epithelium and 73 specimens of dysplasia and carcinoma in situ (CIS) were immunostained with monoclonal antibodies to p53 and Ki-67 to examine the interrelationship between p53, Ki-67 and HPV status in cervical intraepithelial neoplasm. The presence of HPV was assessed by in situ DNA hybridization. Of dysplasias and CIS 79% were HPV positive. The growth rate of neoplastic cells was significantly correlated to the histological grade and the HPV status. The highest proliferation was found in poorly differentiated HPV 16/18 positive precancerous lesions. The analysis of the p53 expression showed no difference between various histological grades. However, the p53 oncoprotein was expressed significantly lower in HPV 16/18 positive neoplasms. The assessment of neoplastic cell growth rate offers a potentially valuable approach to predicting biological behaviour in intraepithelial neoplasms.