Seasonal imbalances between supply and demand for blood products are common. This paper describes a planning system which utilizes conversational computer facilities to assist the manager of a regional or communitywide blood agency in scheduling bloodmobiles and fixed facility collections from one to 18 months in advance. The benefits from changes to only one day of a collection schedule recover the annual costs of using the system, estimated at at $600 for a blood service which collects 65,000 units annually.