What would best motivate more doctors and nurses to work in rural areas of poor countries, where they are badly needed? We presented doctors and nurses in Ethiopia with a series of hypothetical job combinations of wages, working conditions, housing benefits, and training opportunities. For doctors, we found that higher wages and quality housing incentives had the biggest impact on their willingness to practice in towns in rural areas. For nurses, improvements in the availability of medical equipment and supplies were the factors most likely to bring about a move to a rural village. Choosing the right incentive package requires a consideration of both the effects of different packages on health workers' choices and the cost of those packages.