The values of patient autonomy and community participation have become central in health care. However, care practices involve a plurality of possibly conflicting values. These values often transgress the borders of the individual professional–client relationship as they involve family members, other professionals and community organisations. Good care should acknowledge this relational complexity, which requires a collective handling of the tensions between values. To better understand this process, we draw on [Mol, A. 2008. The Logic of Care: Health and the Problem of Patient Choice. Routledge; Mol, A., I. Moser, and J. Pols. 2010a. Care in Practice: On Tinkering in Clinics, Homes and Farms. Transcript Verlag.) by developing the notion of collective tinkering. An ethnographic study was conducted in two teams in community housing services for people with Intellectual Disabilities and Severe Mental Illness. Collective tinkering is analysed (1) within teams; (2) between professionals, family members and professionals from different organisations providing care for the same client; and (3) in organising practices for a collective of clients. Collective tinkering involves assembling goods into a care practice, attentively experimenting with these care practices, and adjusting care accordingly within a collective of those involved in care for a particular client (group). When collective tinkering does not occur, the stakeholders excluded (e.g. clients or family members) may experience poor quality of care.