Objective: The aim of this study was to evaluate the prevalence of abnormal anal cytology in women presenting with abnormal cervical cytology (intraepithelial lesion or cervical cancer) at the largest tertiary university hospital in Thailand. Methods: A cross-sectional prospective study design was used. Anal cytology was performed on 145 women with abnormal cervical cytology between June 2014-Octoble 2014. If abnormal anal cytology was detected, anoscopy was performed with biopsy in any suspicious area of precancerous change. Results: Prevalence of abnormal anal cytology was 5.5% (8 patients). Of 8 patients, six patients presented with low-grade squamous intraepithelial lesion, one patient with high-grade squamous intraepithelial lesion, and one with atypical squamous cell cannot exclude highgrade squamous intraepithelial lesion. Abnormal anoscopic impression was found in 3 cases, as follow: The first case showed faint acetowhite lesion and anoscopic impression was low grade squamous intraepithelial lesion; the second case was reported as human papillomavirus (HPV) change by anoscopic impression; and the third case showed dense acetowhite lesion with multiple punctation and pathologic examination showed anal intraepithelial neoplasm III (AIN3). The last patient underwent wide local excision of AIN3 with split-thickness skin graft reconstruction. Final pathology confirmed AIN3 with free resection margin. Conclusion: Prevalence of abnormal anal cytology was 5.5% in patients with abnormal cervical cytology. The prevalence might be support anal cytology screening in this group of patients.