Historical risk factors of etiologic significance were evaluated in a seroepidemiological prospective study of carcinoma in situ and squamous dysplasia of the uterine cervix among Saudi women in Riyadh. A total of 2,476 women were screened with Papanicolaou smears, and blood samples and cervical swabs were taken for serological study and tissue culture. The results of this investigation show that, although population-based incidence data for Saudi women are generally lacking, the rates of carcinoma in situ and squamous dysplasia of the uterine cervix are very low among Saudis. The related data indicate that in spite of their relatively low mean age at first marriage, at onset of coitus, and at first pregnancy, and an exceptionally high pregnancy rate, the overwhelming majority of screened women had normal cytology (97.6%), while atypical squamous cells were detected in only 2.4% of the sample. Herpesvirus was isolated in 0.5% of the sample, while all these had normal cytology. The findings of this study are consistent with the results of other similar studies on the populationbased data for low-risk groups; the very low rate of cervical malignancies may be ascribed to religious teaching which strongly discourages extramarital relationships, and which also results in low rates of illegitimacy and venereal disease. MeSH KEYWORDS: Carcinoma in situ; Dysplasia, squamous cell; Uterine neoplasms-occurrence; Cervix neoplasms; Cervix dysplasia MORE THAN A century of studies and speculations has been spent on the search for epidemiologic factors of etiologic significance in the onset of carcinoma in situ of the uterine cervix. In this search, three major evidential currents have emerged: (1) demographic resolution of increased risk of women culturally identified by social deprivation and early marriage, (2) epidemiological focus upon sexuality as the core biological association, with early coitus and multiple consorts as the specifically effective components maximizing the risk, and (3) the