This study was designed to identify prognostic factors of patients with cervical cancer stage IB1 undergoingradical hysterectomy. The medical records and specimens of two hundred and five patients with cervical cancerstage IB1 undergoing radical hysterectomy at Songklanagarind Hospital from July 1995 to June 2005 werereviewed. Patients’ age, tumor size, histologic type, tumor grade, depth of invasion, degree of stromal invasion,lymph-vascular space invasion (LVSI), surgical margin status, pelvic node status, and adjuvant treatment wereassessed for correlation with disease-free survival (DFS). The mean age of these patients was 44.2 years and themedian follow up was 56 months. Twenty five patients (12.2%) developed recurrent disease. The overall 5-yearDFS was 86%. In univariate analysis, depth of invasion, degree of stromal invasion, LVSI, and pelvic nodestatus were significant prognostic factors. In multivariate analysis, degree of stromal invasion remained theonly independent prognostic factor. In conclusion, degree of stromal invasion was the main independent predictorof prognosis in surgical cases of cervical cancer stage IB1.