Objectives. To determine progression-free survival (PFS) and overall survival (OS) in women with completely resected stage I or II carcinosarcoma of the uterus treated with adjuvant ifosfamide and cisplatin, and to assess the toxicity of this regimen. Methods. Eligible patients had histologically confirmed carcinosarcoma (mixed mesodermal tumor) and no postoperative radiotherapy following complete resection for clinical stage I or II disease. They were to have adequate renal, hepatic, and hematologic functions and performance status of 2 or less. Study entry was to be within 8 weeks of hysterectomy. Patients with previous chemotherapy, or other noncutaneous malignancies, were ineligible. Ifosfamide was administered 1.5 g/m2 intravenously (IV) over 1 h and cisplatin was given 20 mg/m2 over 15 min followed by mesna 120 mg/m2 IV bolus, then 1.5 g/m2/24 h as a continuous infusion. Initial doses (daily × 5 every 21 days × 3 cycles) were reduced by 20% (to 4 days) for myelotoxicity. Results. Nine of seventy-six patients enrolled were deemed ineligible and another two who did not receive protocol treatment were inevaluable. Of the 65 evaluable patients, median age was 65 years; 50 patients (77%) were stage I and 15 (23%) were stage II. PFS and OS, respectively, were 69% and 82% at 24 months, and 54% and 52% at 84 months. Overall 5-year survival was 62%. Leukopenia was the most commonly reported, but manageable, toxicity. Conclusion. Adjuvant ifosfamide and cisplatin after primary surgery for stage I or II carcinosarcoma of the uterus is tolerable. In the absence of concurrent controls, the impact on PFS and OS is unclear. Pelvic relapse remains problematic.