We attempted a new outpatient treatment using weekly low-dose CPT-11 for advanced colorectal cancer patients. A 73-year-old female with para-aortic lymph node metastases from advanced rectal cancer was given outpatient treatment for more than 5 months with weekly low-dose CPT-11 and HCFU. CPT-11 was given intravenously at a dose of 20 mg/m2 on day 1 every week. On days 2-7, she was treated by oral administration of HCFU (600 mg). Her serum CEA level decreased and continued to do so for more than 5 months. The size of the para-aortic lymph node was reduced by approximately 40%. There were no adverse effects except leukopenia (grade 2). These results suggest that weekly low-dose CPT-11 and oral HCFU may be an effective therapy on an outpatient basis in cases of advanced colorectal cancer.