Introduction: In recent years, the lives of HIV-infected patients in Thailand have improved significantly due to continuous advances in treatment. However, the rate of cancer related to HIV infection (especially cervical cancer) is likely to increase. Although the World Health Organization (WHO) recommends Papanicolaou testing in all HIV-infected women, few of these patients receive this kind of screening in Thailand. Therefore, we conducted this study to evaluate the knowledge, attitudes, and practices of these patients with regard to cervical cancer screening. Materials and Methods: This cross-sectional study was conducted in HIV-infected women aged 18-65 years from April to November 2019 via a self-administered cervical cancer screening questionnaire, which consisted of four parts: demographic data, knowledge, attitudes, and practices. Results: Three hundred HIV-infected women were recruited. Most of the participants had good attitudes toward screening and practiced adequate screening (75.3% and 71.3%, respectively). However, only 62 participants (20.7%) demonstrated adequate knowledge. The crucial factors that were associated with adequate screening practice were age 40-49 years-old (AOR =3.26, 95%CI=1.02-10.37), CD4 cell count (AOR = 3.41, 95%CI = 1.29-8.99), having been advised about cervical cancer screening (AOR= 6.23, 95%CI 1.84-21.07), and attitude toward screening (AOR= 5.7, 95%CI = 2.23-14.55). The major reasons for not undergoing screening were embarrassment (41.86%), lack of symptoms (41.86%), fear of the results (36.04%), and fear of pain (36.04%). Conclusion: The reasons for inadequate testing were disregard and misconceptions about the procedure. To prevent invasive cervical lesions in HIV-infected women, health care providers should inform these patients about the importance of regular cervical cancer screening.