To evaluate whether different qualifications of a cytologic diagnosis of "atypical squamous cells of undetermined significance(ASCUS)" predict a greater or lesser likelihood of tissue diagnosis of uterine cervix, we compared different cytologic qualifications of ASCUS with the tissue diagnosis. One hundred twenty-two consecutive Papanicolaou smears showing ASCUS in women who had undergone cervical biopsy within nearest 30 days were collected. The 122 smears were qualified as "favor reactive"(25%), "favor low grade squamous intraepithelial lesion (LSIL)"(24%), "favor squamous intraepithelial lesion(SIL)"(16%), "favor high grade squamous intraepithelial lesion(HSIL)"(16%), and "not otherwise specified"(19%). Squamous intraepithelial or invasive lesion was pathologically confirmed by cervical biopsy in 13%, of the "favor reactive", 27% in "favor LSIL", 70% in "favor SIL", 75%, in "favor HSIL", and 35% in "not otherwise specified" smears. There were significant associations between the favor reactive smear and the benign biopsy finding and between the favor SIL smear and the biopsy shewing a squamous intraepithelial or more severe lesion. Nevertheless, most of favor LSIL smears exhibit reactive process in tissue biopsy. Conclusively, qualified ASCUS stratifies women Into different risk groups for SIL. The cytopathologist should make the cytologic diagnosis of "ASCUS, favor LSIL" circumspectly.