This study reports the role of information system and technology (IST) in supporting case management at the Accident Compensation Corporation (ACC) of New Zealand. Case management is a managerial approach that seeks to gain improved business performance by enhancing both employee and customer satisfaction. Despite millions of dollars spent annually by health, social, and insurance agencies in automating case management, little research has been conducted into the role of IST in this practice. The findings of this study show that for ACC, IST’s most valuable role is enhancing the relationship between client and case manager rather than replacing it for, even after the addition of IST, the most valuable knowledge continues to accrue from the face-to-face interaction of client and case manager. The findings also show two distinct phases to the development of case managers as knowledge workers. The first phase focuses on control of the processes and the second on the delivery and sharing of information resources.