Since pharmacokinetics in patients undergoing hemodialysis differs from that in patients with normal renal function, chemotherapy for a hemodialysis patient should be considered with due care. We administered chemotherapy of modified FOLFOX6 to a patient on hemodialysis with inoperable metastatic colorectal cancer, and measured his plasma concentration of total platinum and non-protein-bound platinum. Since there is no reported case of oxaliplatin use in patients on hemodialysis so far, we evaluated whether it could be safely used for such patients. We made a dose escalation study with 40, 50, 60, 70 and 85 mg of oxaliplatin, and evaluated the pharmacokinetics at each dose. AUC was 5.67-10.21 mg/L x h. The dialysis removal rate was 84.0%. Although this patient could accept it relatively safely without any severe side effect, the optimal dosage and the timing of hemodialysis for inoperable metastatic colorectal cancer patients should be determined by a further study using more cases.