Private-public mix (PPM) DOTS is widely advocated as a DOTS adaptation for promoting progress towards the international tuberculosis (TB) control targets of detecting 70% of TB cases and successfully treating 85% of these. Private health care plays a central role in health-care provision in many developing countries that have a high burden of TB. It is therefore encouraging that PPM projects are being set up in various countries around the world to explore possible interaction between the national TB programmes and other partners in the fight against TB. The objective of this review was to use the published literature to assess the range of providers included in PPMs for their ability to provide case-detection services for the vulnerable. From a case-detection perspective, we identify the essential elements of a pro-poor PPM model, namely, cost-effectiveness from a patient perspective, accessibility, acceptability and quality. The review revealed that a very large part of the total spectrum of potential PPM-participating partners has not yet been explored; current models focus on private-for-profit health-care providers and non-governmental organizations. We conclude that it is important to think critically about the type of private providers who are best suited to meeting the needs of the poor, and that more should be done to document the socioeconomic status of patients accessing services through PPM pilots.