For process innovation or process management, which has been actively adopted by firms in recent years, to take root, organizational structure must also undergo fundamental changes toward a process orientation. However, the existing literature on process organizations has been biased toward prescriptive and normative perspectives, resulting in insufficient understanding of process organizations and abstract discussions. Based on theoretical examination and case studies of domestic and international firms, this paper derived various types of process organizations. As hybrid structures, process organizations come in diverse forms, and their structural characteristics and effective operational methods differ by type. Additionally, effective methods for organizing processes based on process characteristics when implementing them in firms were presented. Finally, propositions were offered from a contingency perspective regarding the relationships between situational factors—such as environment, firm characteristics, and competitive strategy—and process organizations. The process organization is not a panacea suitable for all types of firms. Process organizations are more appropriate for firms operating in environments where technological uncertainty is not high but customers are differentiated and possess strong bargaining power. Furthermore, they are most effective and have the greatest potential for application in large, mature firms where capabilities are well established in each division, where specialized expertise in particular functional areas no longer serves as a source of competitive advantage, and where the organization has undergone extensive horizontal differentiation and bureaucratization due to its large scale and long history. Additionally, process organizations are judged to be more effective for firms pursuing marketing differentiation strategies rather than cost leadership or technological differentiation strategies.