Describes a computer model to aid decisionmakers in the health services field in developing countries. As developing countries increasingly depend on user fees to finance health care services, decisionmakers in those countries face the difficult task of developing and implementing cost-recovery systems. In recent years health economists have developed computer models to aid in such analyses. This paper contains a user-friendly computer model on a 3A' diskette which combines information about demand and supply for health care obtained through surveys undertaken in Zaire. It allows the user to enter data from other settings and to simulate various changes in health care financing under a broad range of circumstances. The computer model is provided as a tool for users to assess the impact of health financing policies on health care use and health facility financial performance. The model has been developed in Lotus 1-2-3 and is contained in four spreadsheet files that can be run on any IBM- compatible microcomputer with at least 640 kilobytes of RAM memory. The paper explains in detail the assumptions and theory behind the model, and presents numerous simulations to illustrate how the model can be used. The capabilities and limitations are also outlined, along with a summary and conclusions.