To know the correlation of punch-biopsy proven cervical intraepithelial neoplasia (CIN) 3 with the results of cone and hysterectomy. Methods We reviewed the medical records from 1999 to 2008, retrospectively, at a single institution. We checked age, cone and hysterectomy biopsy results, preoperative cervical smear results as well as human papillomavirus results. Results There were 104 patients whose punch biopsy results were CIN 3. 59 (56.7%) patients underwent cone and 45 did hysterectomy after punch biopsies. Cone found 6.8% of cervical cancer. Among patients undergoing hysterectomy without cone, 8.9% had cervical cancers. There were a lot of inflammations, atypical squamous cells of unknown significance, low-grade squamous intraepithelial lesion done as a Pap results just before cone. The positive rate of HPV was 80.0%. There were 5.1% of underestimated and 6.8% of over-estimated results according to the cone results, and 6.7% of under-estimated and 8.9% of overestimated according to the hysterectomy results. Conclusion Through conization, 93.2% of the patients whose punch biopsy results were CIN 3 had CIN and did not need hysterectomy, and 6.8% had cervical cancers and might need further treatment. Through hysterectomy, 91.2% had CIN and might undergo overtreatment.