From January 1990 to December 2004, the prognosis of 28 patients with stage Ib1 adenosquamous cell carcinoma (ASC) were assessed in comparison with those of matched counterparts of pure adenocarcinoma (ADC) and squamous cell carcinoma (SCC). The mean ages were 46.6, 48.3, and 48.5 years for patients with ASC, ADC, and SCC, respectively. All the patients underwent radical hysterectomy with pelvic lymphadenectomy and postoperative adjuvant therapy was given to the patients with positive pathological risk. The incidence of lymph node metastasis for ASC at 21.4% was not significantly different from those for ADC (13.6%) and SCC (15.8%). There was also no significant difference in the incidence of lymphatic or vascular space involvement (LVSI) and depth of stromal invasion between three cell types. Since the tumor sizes of all ASC cases examined in this study were less than 4 cm, the prognoses were compared among stage Ib1 disease according to the classification system of the International Federation of Gynecology and Obstetrics (FIGO). The overall 5-year survival rates of stage Ib1 ASC, ADC, and SCC were 82.4%, 92.4%, and 94.0%, respectively, suggesting poor prognosis of ASC, but there was no significant difference. Patients with stage Ib1 ASC were retrospectively assigned to a low- or high-risk group based on the surgical-pathologic factors including positive lymph node metastasis, 2-4 cm of tumor size, positive LVSI, and/or deep stromal invasion. While all 9 patients in the low-risk group are alive without disease, 7 of the 19 patients in the high-risk group developed recurrence. The overall 5-year survival rates were 100% for a low risk group and 74.8% for a high-risk group, respectively, but this difference did not reach statistical significance. However, the prognosis of high-risk patients with lymph node metastasis was significantly (p=0.01) worse than low-risk group. The present study suggests that ASC histology appears to carry a poor prognosis than SCC, but low-risk group of stage Ib1 ASC has a good prognosis without postoperative adjuvant therapy.