Decentralized case-based reasoning (DzCBR) is a reasoning framework that addresses the problemof adaptive reasoning in amulti-ontology environment. It is a case-based reasoning (CBR) approach which relies on contextualized ontologies in the C-OWL formalism for the representation of domain knowledge and adaptation knowledge. A context in C-OWL is used to represent a particular viewpoint, containing the knowledge needed to solve a particular local problem. Semantic relations between contexts and the associated reasoning mechanisms allowtheCBRprocess in a particular viewpoint to reuse and share information about the problem and the already found solutions in the other viewpoints.