Abstract: This article addresses problems of accountability in the system of multilevel governance, organised around networks, as it exists in the EU. An ‘accountability deficit’ arises when gaps are left by the accountability machinery of the several levels of government, supranational and national. This article suggests a new evaluative framework based on the concept of ‘accountability network’, questioning the hierarchical and pyramidal assumptions that presently underpin accountability theory in the EU context. Using case studies of the Community courts and European Ombudsman, the article suggests that ‘accountability networks’ may be emerging, composed of agencies specialising in a specific mode of accountability, which come together or coalesce in a relationship of support, fortified by shared professional expertise and ethos. At present fragmentary and imperfect, these might ultimately be capable of providing effective machinery for accountability in network governance systems.