This thesis explores the interconnection between old and new actors as well as programs for conflict management in the workplace: unions and Integrated Conflict Management Systems (ICMSs). ICMSs are designed to provide an interconnected web of conflict resolution options and services to employees with ultimate aim of creating organizations that can productively manage conflict. Given that ICMSs have primarily been used by and researched in non-union organizations, this study investigates the interaction of ICMSs with traditional conflict resolution approaches and procedures found in unionized workplaces. Using a comparative case research design, the study investigates the reasons why three local unions in a large U.S. government agency take different positions on the desirability of a conflict management system. It finds the level of alignment between local union goals and strategies and local management goals and strategies is the key factor explaining the divergent union approaches. The thesis proposes a model of union engagement with conflict management systems and discusses the implications of such a model for conflict management system theory.