Purpose – In an urban environment in The Netherlands, a municipality, a health insurance company and nine health care organisations try to integrate health care services and social services by means of a global, population-based budget for three areas with above the average costs. Against a background of changing circumstances and bureaucratic impediments, they try to reach an agreement on the contractual provisions before starting cooperation in everyday practice. The purpose of this paper is to describe and evaluate the cooperative process. Design/methodology/approach – The paper reflects the authors’ personal experiences and interpretation of the cooperative process. Findings – The participants experience was that the ideals they had started with faded when financial and juridical procedures dominated the discussions. In contrast with that, focusing on the population involved created positive energy and motivation. Practical implications – Uncertainties are part of social innovation and therefore, formal contracts will be incomplete. Trust building techniques and creating common values and culture are necessary ingredients for developing confidence that the cooperating parties will be able to cope with unforeseen developments or outcomes. Originality/value – The paper may contribute to the successful development of innovative agreements between purchasers and providers of health care and social care in order to achieve better integrated services without rising costs.