Background: NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) are the most commonly used guidelines in the US and globally, and aim to improve and facilitate quality, effective, efficient and accessible cancer care. The guidelines are constantly updated, as such, the number, scope, length and detail have continuously increased, which has placed challenges for clinicians to remain up to date. Solutions are highly needed to improve the usability and implementation of the NCCN Guidelines. The NAVIFY Guidelines application was developed to provide digitised NCCN Guidelines, to facilitate navigation, and to enable the real-time capture of clinical decisions, including reasons for deviation from guidelines. We assessed the usability and performance of the NAVIFY Guidelines application. Methods: A 60-minute remote, semi-structured interview and task-based user test was undertaken with 10 medical oncologists from diverse geographies (6 US, 2 UK, 2 Germany). No participants had prior experience with the digital solution. Participants tested the experience of using the NAVIFY Guidelines application on their computer by completing tasks for one of 3 tumor types (breast, lung or AML). Screen and audio activities were recorded via Zoom. At the end of the test, participants were asked to rate the performance of NAVIFY Guidelines and complete statements on a System Usability Scale (SUS) questionnaire. Results: NAVIFY Guidelines SUS score was on average 82.3 (80.8 – 84.0), classified as A score (i.e., excellent; NPS [net promoter score]: promoter level). Success ratings across all 6 tasks was 86%, as shown in Table1. The overall impression from participants was largely positive. "Ease of use" was the most salient theme followed by “logical structure” and the “value of being integrated with patient data”. Participants identified that the key value of NAVIFY Guidelines was improving communication between the care team and improving the documentation of guideline adherence. 3 participants saw the potential in teaching settings. Conclusions: NAVIFY Guidelines has been developed to support clinicians to apply the latest clinical recommendations, improve the documentation of decisions and to facilitate better communication between specialists, and with patients. Preliminary research has shown that NAVIFY Guidelines has excellent usability (score A) & high NPS. Overall NAVIFY Guidelines was perceived as easy to use, valuable to improve communication between care teams and helpful at easing documentation burdens.