Purpose: The Working Group of the Gynecological Tumor Committee of the Japanese Radiation Oncology Study Group (JROSG) published recommendations for contouring high-risk clinical target volumes (HR-CTV) on CT for 3-dimentional image-guided brachytherapy for cervical cancer. The purpose of this study was to compare HR-CTV delineated on CT, referencing recommendations from JROSG, with HR-CTV delineated on MRI, referencing consensus guidelines from the Groupe Européen de Curiethérapie-European Society for Therapeutic Radiology and Oncology (GEC ESTRO)., Material and Methods: Fourteen patients were evaluated. After the insertion of the CT/MR applicator into the patient, CT and MRI were performed. HR-CTV MR was delineated on MRI for clinical examination and HR-CTV CT was delineated on CT retrospectively referencing the MRI just before brachytherapy within a week. The volume and dosimetry of HR-CTV based on a 6 Gy dose of the Manchester system were evaluated., Results: The median volumes of HR-CTV MR and HR-CTV CT were 24.4 ml (range, 13.6-50.4 ml) and 29.9 ml (range, 13.2-49.2 ml), respectively. Median D 90 of HR-CTV MR and HR-CTV CT were 6.7 Gy (range, 5.8-10.1 Gy) and 6.8 Gy (range, 5.1-10.4 Gy), respectively., Conclusion: Somewhat difference could be seen between HR-CTV MR and HR-CTV CT .