This study was undertaken to evaluate the incidence and severity of residual lesions in women featuring highgradesquamous intraepithelial lesion (HSIL) histology with endocervical cone margin involvement after the loopelectrosurgical excision procedure (LEEP). The medical records of women undergoing LEEP at Chiang Mai UniversityHospital between October 2004 and February 2006 were retrospectively reviewed and 74 cases were identified.Nineteen women were excluded because of loss to follow-up. The remaining 4 were referred to other hospitals and 2declined re-excision, leaving a study population of 55 women for analysis. Mean age ± SD of the patients was 48.5 ±8.9 years. Residual lesions were noted in 26 (47.3%, 95%CI= 33.7 to 61.2). Four (7.3%) had unrecognized invasivecervical carcinoma in subsequent specimens. In conclusion, approximately half of women with positive endocervicalcone margins after LEEP for HSIL histology have residual disease. Repeat diagnostic excision is recommended forevaluation of lesions and severity.