PurposeThe purpose of this paper is to show how the viable system model (VSM) and de Sitter's design theory can complement each other in the context of the diagnosis and design of viable organizations.Design/methodology/approachKey concepts from Beer's model and de Sitter's design theory are introduced and analyzed in order to show how they relate.FindingsThe VSM provides insight into the related systems necessary and sufficient for viability. As such, it specifies criteria supporting the diagnosis and design of organizational infrastructures, i.e. of organizational structures, HR systems, and technology. However, it does not explicitly conceptualize and provide a detailed heuristic for the design of organizational structures. De Sitter's theory fills in this gap.Originality/valueThe paper illustrates how, based on a rudimentary model of organizational viability, de Sitter's design theory positively addresses the question of how to diagnose and design organizational structures that add to the viability of organizations.