Résumé : Background In their mission to achieve better access to quality healthcare services, mutual health organisations (MHOs) are not limited to providing health insurance. As democratically controlled member organisations, MHOs aim to make people's voices heard. At national level, they seek involvement in the design of social protection policies; at local level, they seek to improve responsiveness of healthcare services to members' needs and expectations. Methods In this qualitative study, we investigated whether MHOs in the Democratic Republic of Congo (DRC) succeed in defending members' rights by improving healthcare quality while minimising expenses. The data originate from an earlier in-depth investigation conducted in the DRC in 2016 of the performance of 13 MHOs. We re-analysed this existing dataset and more specifically investigated actions that the MHOs undertook to improve quality and affordability of healthcare provision for their members, using a framework for analysis based on Hirschman's exit-voice theory. This framework distinguishes four mechanisms for MHO members to use in influencing providers: (1) 'exit' or 'voting with the feet'; (2) 'co-producing a long voice route' or imposing rules through strategic purchasing; (3) 'guarding over the long voice route of accountability' or pressuring authorities to regulate and enforce regulations; and (4) 'strengthening the short voice route' by transforming the power imbalance at the provider-patient interface. Results All studied MHOs used these four mechanisms to improve healthcare provision. Most healthcare providers, however, did not recognise their authority to do so. In the DRC, controlling quality and affordability of healthcare is firmly seen as a role for the health authorities, but the authorities only marginally take up this role. Under current circumstances, the power of MHOs in the DRC to enhance quality and affordability of healthcare is weak. Conclusion On their own, mutual health organisations in the DRC do not have sufficient power to influence the practices of healthcare providers. Greater responsiveness of the health services to MHO members requires cooperation of all actors involved in healthcare delivery to create an enabling environment where voices defending people's rights are heard.