Purpose: The PAP smear has significantly reduce the mortality and morbidity of cancer cervix however there is some debates of it as interobserver variability and high false negative and false-positive rates so parameters of cell proliferation have emergedas important diagnostic and prognostic tools. Aim of the work : This present study aimedtoevaluate the efficiency of Ki67 in differentiating dysplastic lesion from benign lesion of cervical cytology smear. PatientsandMethods:This cross-sectional studyincluded67 cases of cervicovaginal cytology smear of all gynecological cases in Benha University Hospital and Early Cancer Detection Unit, Pathology Department, Benha faculty of Medicine during the period of October 2014-May 2015. Immunocytochemical Ki67 expression was both graded as well as Labelling Index was calculated. Statistical evaluation was carried out using the Fisher’s Extract test, Student t test (p