PURPOSE: To determine whether the outpatient loop electrosurgical excision procedure (LEEP) conization (out-LEEP) is as effective and safe as inpatient LEEP conization (in-LEEP) with regard to the complete removal of cervical dysplasia, recurrence-free survival and post-operative morbidity. METHODS: 233 patients were included in this retrospective cohort study from January 2002 to December 2007. 181 had outpatient treatment and 52 inpatient treatment. We used Mann-Whitney U test, two-sided Fisher's exact test, Chi-square test, log rank test and Kaplan-Meier curve. RESULTS: Incomplete excision was found in 16/52 (30.8%) cases in the inpatient group and 46/181 (25.4%) in the outpatient group (P = 0.48). Six patients had post-operative complications: two cases of secondary haemorrhage in each group (in-LEEP 3.8%, out-LEEP 1.1%, P = 0.22) and two cases of cervical stenosis amongst inpatients (3.8%, P = 0.049). Alteration of specimen by thermal artifact were reported in 4/52 (7.7%) of in-LEEP cones and 10/181 (5.5%) of out-LEEP cones (P = 0.52). Measurements of cones in both groups were comparable with a mean depth of 9.35 mm (±5.5 mm) and 8.4 mm (±3.4 mm), respectively. CONCLUSION: Our results suggest that efficacy and safety of ambulatory LEEP conization is comparable as in inpatient procedure.