OBJECTIVE: To investigate whether there is a regeneration process after cervical conization and, if it exists, how much of the cervix will regenerate and when regeneration will be completed. METHODS: This was a prospective observational study of women undergoing conization for cervical intraepithelial neoplasia. Transvaginal ultrasonographic examinations of the cervical volume and length were performed just before conization and were repeated at 1, 3, 6, 9, and 12 months after conization. The volume and length of the cone excised were assessed with a volumetric tube and a vernier caliper, respectively. RESULTS: Of 99 women recruited for this study, 75 completed the 12-month follow-up. Cone volume and depth excised were 27.4+/-9.2% and 38.9+/-13.8% of the baseline, respectively. The steady increase of cervical volume after conization was statistically significantly until 6 months, but no further increase was observed from 6 to 12 months. At the 12-month follow-up, the cervical volume was 14.0+/-4.2 cm(3), which corresponded to 93.1+/-19.1% of the baseline with a statistically significant difference between the baseline and 12-month follow-up (P=.006). These cervical regeneration patterns were also observed in cervical length. CONCLUSION: The time of regeneration completion was 6 months after conization, and the cervical dimensions after completion of the regeneration process were more than 90% of the initial measurements.