The cell cycle is composed of a series of steps which can be negatively or positively regulated by various factors. p53 gene aberrations are common in human malignancies, and recent studies suggest that in cervical carcinoma p53 function is inactivated either by complex formation wilh human papilloma virus (HPV) E6 product or by gene mutation. To study the expression of p53 gene in the cervical cancer and cervical intraepithebal neoplasia, immunohistochemistry for the p53 protein was done in the 47 cases of squamous cell carcinoma, 6 cases of adenocarcinoma and 32 cases of cervical intraepithelial neoplasia. I. The p53 protein was detected in the 31% of cervical intraepithelial neoplasia (10/32 cases). 2. The p53 protein was detected in the 55% of invasive cervical cancer (29/53 cases). 3. By the histologic type of cervieal cancer, the p53 protein was detected in the 57% of squamous cell carcinoma (27/47 cases) and 33% of(2/6 cases) adenocarcinoma. The p53 protein wes more frequently detected in the squamous cell carcinoma than in the adenocarcinoma. 4. By the staging in cervical cancer, the p53 protein was detected in the 31% of stage 0, 50% of Stage Ia, 50% of stage I b, 75% of IIa and 50% of stage II b.