Currently the chemotherapeutic agents available for intra-arterial infusion in metastatic liver cancer are limited to only a few. The recent demonstration of the feasibility of prolonged IV infusion of vincristine led to exploration of hepatic intra-arterial infusion of this agent. A continuous infusion of 0.4 mg total dose was administered daily for 5 days via a hepatic artery catheter to each of six patients with metastatic liver cancer. Transient but life-threatening toxicity principally involving the nervous and gastrointestinal systems occurred in five of them. Future investigation of hepatic intra-arterial infusion of vincristine should be based on dose-schedules other than that employed in the current trial.