Introduction: Health researchers often face difficulties related to participants' recruitment for their research. However, a new strategy emerges: offering patients-but also citizens who are not ill-the possibility to volunteer as participants to hasten research processes. The French platform "Seintinelles" aims to fulfill this goal and bring together citizens who volunteered to participate to cancer related research. The "Seintinelles Barometer" aims to describe these volunteers' profile. Methods: The Seintinelles Barometer data were collected through a web-based auto-questionnaire proposed to the "Seintinelles" members from June 2017 to November 2018. Results: The sample presents a high level of overrepresentation of women. Participants are characterized by a high level of education. About a third of the participants had suffered from cancer. Two profile of volunteers emerged: the « patients » and the « supportive citizens ». Discussion: The Seintinelles Barometer participants manifest a strong wish to be involved in cancer related research. Therefore, this platform seems to be a promising tool for the development of community-based research in the field of cancer.