209 Background: As the oncology community increasingly acknowledges the time burdens of cancer care, there is a critical need for foundational work to understand the sources, populations impacted, and consequences of time toxicity. We sought to evaluate these through qualitative interviews. Methods: We conducted semi-structured interviews with adults with advanced stage gastrointestinal cancer, informal care partners, and clinicians at an NCI-designated cancer center in MN, USA from Feb-Oct 2023. We explored aspects of cancer care that took up time and were perceived as burdensome, identified those most impacted, and the consequences. We recorded and transcribed interviews, and conducted inductive thematic analysis. Results: We interviewed 47 participants [16 patients (8 <60 years; 12 women), 15 care partners (10 <60 years; 9 women), and 16 clinicians (including advanced practice providers, nurses, physicians, schedulers, and social workers; 11 women)]. We identified 22 subthemes that we grouped into 5 themes (Table). Conclusions: This multi-stakeholder qualitative analysis provides a deeper understanding of time toxicity. These data will help the oncology community to map, measure, and ultimately address time toxicity. Theme Subthemes Illustrative quotes Source: Healthcare outside the home Travel, parking, and, waiting time, planned appointments, unplanned care, hospitalizations and facility-based care '’My wife and I made over 100 drives in two years, over an hour and a half in each direction.’’ (Patient) Source: Often invisible tasks performed at home Logistic and administrative tasks, learning about the disease and treatment, medical management, time spent managing symptoms and on recovery, home-based care ‘’A large burden was like the insurance paperwork.’’ (Care partner)‘’And that has happened before where I've just spent the whole day at home waiting for home care.’’ (Patient) Populations impacted: Care partners alongside patients Care partners are equally affected, taking over social responsibilities/ tasks of daily living ‘’Anything that takes time for me, is almost an equal burden on her. If not more sometimes.’’ (Patient) Consequences Care becomes all-consuming, short visits turn into ‘’all-day’’ affairs, missing important life events/work, emotional distress, demoralization, financial burdens ‘’ It’s like I am always on a leash. I really don't have any control.’’ (Patient)‘’Even for a 30-minute infusion, you'll be there, like half a day or a whole day.’’ (Patient) Positive interactions and hope for change Not all time spent is perceived as burdensome, clinicians are hopeful of decreasing time burdens, clinicians recognize their own time burdens as a barrier to addressing patients’ ‘’Patients having to walk through this incredibly long, circuitous way to check in, do labs as ritual—we are disdainful of a patient's time. We should demand change.’’ (Clinician)