OBJECTIVES: To provide an overview of the principal areas of research on health care organization and service delivery and to identify priority areas from a European comparative perspective. Given the large quantity of articles produced on health care organizations, we focus on primary care and hospital care. METHOD: A combination of methods was used for describing past and current research: (i) bibliometric analyses of published research in Pubmed and Embase 2000-09; (ii) a further classification of research based on a sample of 1,010 articles; and (iii) an identification of relevant EU-funded projects over the period 2000-10. An online survey of experts was carried out to identify priorities. The results were refined through conference discussions. RESULTS: Research into health care organizations varies considerably across Europe. This is only partly associated with differences in countries' gross domestic product or population. Studies were categorized into four main domains: intra-organizational control; inter-organizational relations; patient relations; and governance and accountability. Past and current research may not reflect future priorities as the domain of 'inter-organizational relations' is regarded by most experts as the top priority for the future, while the smallest share in the sample of published research and EU-funded projects fell into that category. Expert views show considerable homogeneity, regardless of their role in the health care system or their country. Specific future priorities include the integration of care across organizational boundaries (including the relationship between primary and secondary care), patient involvement and participation and workforce skill-mix. CONCLUSIONS: The research priorities identified in this study relate to important shared challenges in Europe's health care systems. This makes cross-border learning important, especially given the clear geographical variation in health services research (HSR) funding and capacity in Europe.