Purpose – In the last decade, greater attention has been paid to the role of management accounting and control (MAC) in making professional organizations more horizontal. The authors argue that earlier research has not shown how the interrelatedness between professional identities and MAC influences attempts to make organizations more horizontal. In this paper the authors respond to the call for more research on the relationship between horizontalization and accounting and control. The purpose of this paper is to contribute to the emerging literature on the relationship between accountability arrangements and professional identities. Design/methodology/approach – Theoretically the authors have an actor-network theory (ANT) approach. Empirically, the authors followed two episodes where actors at top management levels in two Swedish health care organizations introduced horizontalization. Findings – The two episodes support the view that the role of MAC when making professional organizations more horizontal is limited. Professionals dominate what happens at the operational level and they do not act on MAC rules and performance targets in opposition of their professional identity. However, in alliance with other interessement devices MAC may have a role in creating overflows, that is, pointing out imperfections in the existing frame. The authors noticed no signs that professionals developed hybrid identities as in previous research. Originality/value – The authors apply ANT to move beyond the commonly used contingency and new institutional sociology perspectives. © 2016, © Emerald Group Publishing Limited.