A central theme of recent health care reforms has been a redefinition of the roles of the state and private providers. With a view to helping governments to arrive at more rational "make or buy" decisions on health care goods and services, we propose a conceptual framework in which a combination of institutional economics and organizational theory is used to examine the core production activities in the health sector. Empirical evidence from actual production modalities is also taken into consideration. We conclude that most inputs for the health sector, with the exception of human resources and knowledge, can be efficiently produced by and bought from the private sector. In the health services of low-income countries most dispersed production forms, e.g. ambulatory care, are already provided by the private sector (non-profit and for-profit). These valuable resources are often ignored by the public sector. The problems of measurability and contestability associated with expensive, complex and concentrated production forms such as hospital care require a stronger regulatory environment and skilled contracting mechanisms before governments can rely on obtaining these services from the private sector. Subsidiary activities within the production process can often be unbundled and outsourced.