In order to improve the design of information systems for notifiable conditions reporting, it is essential to understand the role of such systems in public health practice. Using qualitative techniques, we performed a task analysis of the activities associated with notifiable conditions reporting at a large urban health department. We identified seventeen primary tasks associated with the use of the department's information system. The results of this investigation suggest that communicable disease information management takes place in a dynamic environment where changing needs may require new solutions for system users. Additionally, our work suggests that task analysis, when applied to document the use of a legacy information system, can provide local public health agencies with valuable information about their information management needs, and can become a part of their information management decision-making strategy.