Delays in the process of diagnosing and treating cancer are common and lead to confusion and undesirable outcomes. Care coordinators are often embedded within the system of care to manage follow-up care. Electronic and real-time reminder systems can be used to support the care coordinator’s work, but electronic health record (EHR) usability is known to be poor. This study, completed in collaboration with the Department of Veterans Affairs (VA) Connecticut Healthcare System, evaluated the Cancer Coordination and Tracking System (CCTS), an EHR-linked, web-based tool for cancer care management. A set of expert-driven and user-driven usability engineering methods was applied to comprehensively identify and analyze usability problems within the system. Ten current CCTS users were engaged in the study to help identify problem. 101 (62.3%) problems were identified through expert-driven methods, 56 (34.6%) were identified by user-driven methods, and 5 (3.1%) were identified through both types of methods. The list of 162 unique problems were prioritized and twelve high priority problems were highlighted. Design recommendations were developed to address each of these high priority problems.