The PAP immunocytochemical technique utilizing specific keratin antibody was applied to paraffin sections from 36 cervical biopsies. Normal squamous eptihelium and condylomas had similar patterns of keratin production with intense staining of intermediate and upper layers, while basal cells remained negative. Dysplasia, carcinoma in situ and infiltrating squamous carcinoma showed uneven distribution of keratin with the least amount seen in the areas with high mitotic rate and anaplasia. All large cell squamous carcinomas demonstrated presence of significant amouts of keratin. Squamous carcinomas of the small cell type were essentially keratin-free.