This paper describes the efforts of Family Health International to develop a simple, standard and replicable methodology to estimate expenditures on family planning in developing countries. The study found that it is not possible, at least at this time, to develop such a methodology. Numerous problems were encountered in making expenditure estimates. First and most important, expenditure accounts are not always readily available. Even when these accounts are available, they may require some adjustments. In some instances, for example, the salaries of health workers who also provide family planning are in the health accounts, whereas in other cases the workers covered in the family planning accounts spend some of their time providing health services. Allocation variables then must be developed to separate spending on family planning from that on health. In some instances allocation variables were developed and used to separate family planning from health expenditures, but in this case allocation variables were not available and a cost analysis was performed. It is concluded that it takes considerable time and effort to estimate expenditures, and that the approach that was followed varied by country, reflecting the data available to make estimates.