Objective: To evaluate the efficacy, toxicity and factors affecting the survival rate of patients treated with irinotecan. Subjects and Methods: Data from the medical records of 74 patients who had recurrent/metastatic colorectal cancer treated with single-agent irinotecan were analyzed. Results: The mean age for all the patients was 56 years (range 19-77). Forty-one (55%) and 33 (45%) patients had recurrent and/or metastatic colon cancer, respectively. All the patients were treated with irinotecan 350 mg/m(2) every 21 days. Grade 3-4 emesis, grade 3-4 diarrhea, grade 3-4 neutropenia and severe early cholinergic events developed in 7, 15, 7 and 1.3% of patients, respectively. One patient died due to acute renal failure. The overall response rate was 14% (complete response 5%, partial response 9%); 61% had stable response while another 25% had progressive disease. Patients with multiple metastatic foci, patients <= 50 years of age and patients with peritonitis carcinomatosa were shown to have worse outcomes than others. The median duration of response was 16.7 months. The median progression-free survival and overall survival were 4 and 14 months, respectively. Conclusion: The data show that irinotecan was useful in the treatment of recurrent/metastatic colorectal cancer with acceptable toxicity. Copyright (C) 2006 S. Karger AG, Basel.