The purpose of this paper is to analyse the process by which donors decide whether or not to support specific primary health care projects. First of all, there has to be an 'eligible situation': an inability to start without external support, coupled with an ability to sustain the project (without such support) once it has started. Secondly there must be an 'eligible project', that is, a project that requires support of a 'one-time-only' nature (for example, capital outlay); or recurrent support to temporary activities (such as salaries for a temporary campaign), or temporary support to recurrent activities (for the initial stages of innovative programmes). Proposals for really innovative programmes are seldom readily available, and the most appropriate form of support may then be to support an institution charged with the development of such innovative programmes.