The cytologic screening experience of the University of New Mexico Cytopathology Laboratory was reviewed for a nine-year period in order to evaluate the potential for progression of cervical squamous dysplasia to severe dysplasia and carcinoma. Entry conditions for dysplasia study were two initial negative smears in order to standardize the cytologic history to a reasonable extent. Relative likelihood of progression was calculated for three levels of cytologic dysplasia and was compared to those of negative and positive smears in order to ascertain the relative risk of the various levels of cytologic atypia. Slight, moderate an severe dysplasia were, respectively, 9.0, 26.3 and 83.3 times more likely than a negative smear to be followed by one positive for carcinoma or showing severe dysplasia. Histologic follow-up of study subjects was correlated with their cytologic history. Cytologic follow-up of patients with slight, moderate and severe dysplasia indicated a high spontaneous regression rate. Time for conversion from negative cytology to severe dysplasia or positive cytology for histologically confirmed cases averaged 3.0 years. An unexpected finding was a 12.5% false-negative rate for severe dysplasia and positive cytology, indicating a need for caution in advising repeat smears in lieu of a biopsy for confirmation of these findings.