Hulka, B. S. (School of Public Health, Univ. of North Carolina, Chapel Hill, N.C 27514) and C. K. Redmond. Factors related to progression of cervical atypias. Amer J Epidem 93: 23–32, 1971.—Five hundred thirty-nine women with atypical cervical smears underwent long term follow-up to determine factors associated with cytologic progression. Life table analysis on prevalent atypical smears revealed a cumulative probability of progression of 41.2% after 5 years' follow-up. The probability of progression was greatest in the first 6 months, 13.6%. After the first year of follow-up, the progression rate was 3–4% in each 6-month interval. For incident atypical smears the cumulative probability of progression was 17.6% after 2½ years of follow-up with no progression thereafter. The semi-annual progression rates for incident atypical smears was approximately half that of prevalent atypical smears, If the first follow-up smear was negative, lower progression rates ensued than if it was atypical. Progression rates were high among women 30–44 years of age and lowest in Negroes less than 30. Numerous socioeconomic variables were revieweo but no associations with progression were found.