This article develops a formal theory of the structural aspects of organizational change. It concentrates on changes in an organization’s architecture, depicted as a code system. It models the common process whereby an initial architectural change prompts other changes in the organization, generating a cascade of changes that represents the full reorganization. The main argument ties centrality of the organizational unit initiating a change to the total time that the organization spends reorganizing and to the associated opportunity costs. The central theorem holds that the expected deleterious effect of a change in architecture on the mortality hazard increases with viscosity and the intricacy of the organizational design.