Pharmacokinetic properties of many antineoplastic agents or their metabolites change with organ dysfunction. Unfortunately, chemotherapy doses determined in phase I and II studies in patients with normal hepatic and renal reserves are not usually applicable to those with hepatic and/or renal dysfunction. Considering the high incidence of colorectal adenocarcinoma, it is not unusual for a colorectal cancer patient to be on chronic hemodialysis. We report a patient with metastatic colorectal cancer on chronic hemodialysis who tolerated weekly irinotecan at 50 mg/m2 well without significant toxicity. We briefly discuss therapeutic dose modification in such patients.