Information technology outsourcing relationships between clients and suppliers are generally embedded into formal contracts. The empirical literature on contracting usually assumes that contractual completeness is difficult to achieve due to the transaction costs of describing—or of even foreseeing—the possible states of nature in advance. Little research has been done on the on-going set of processes during the life of the client/supplier relationship in the post phase of the contract where unforeseen contingencies and events emerge. Hence, a process improvement framework for studying IT outsourcing relationships is needed to provide more detailed metrics for assessing and managing the maturity level of IT outsourcing relationships. The purpose of this paper is to develop and validate an evolutionary process improvement model to manage relationships between clients and suppliers in the context of information technology outsourcing. We call this model the Capability Maturity Model of Information Technology Outsourcing Relationships (CMMITOR). The model presents the key elements of maturity in IT outsourcing relationships from an ad hoc stage, immature relationship management processes to highly mature and disciplined ones. The preliminary results show that the process-view of IT relationships is suited for this purpose. Key process areas were identified and refined through a card sorting procedure. The validation of the resultant model is underway through a field study of ten IT outsourcing relationships. Implications for research and practice are discussed.