11058 Background: Telemedicine services have great potential to improve access to care of cancer patients who are vulnerable in health status and may experience financial hardship due to the cost of their care. However, very little is known about how the Centers for Medicare and Medicaid Services’ waiver of reimbursement restrictions on telemedicine and characteristics of cancer affected their use of telemedicine services. We examined the changes in frequency of telemedicine use before and after the waiver and, after the waiver, the determinants of telemedicine use across medical provider types. Methods: We used the 5% Surveillance, Epidemiology and End Results registry file linked to Medicare data among patients who had a newly diagnosed cancer in 2019 and were enrolled in Medicare Parts A and B during 2019-2020, and Area Health Resources File. Our outcomes were binary variables of telemedicine services use in outpatient (OP), office-based clinics (OB), and emergency department (ED), respectively, and for detailed provider types in OB. Primary independent variables included the ten most frequently observed cancer sites (reference: all other sites), sequence of cancer, stage of diagnosis, and quarter of diagnosis in 2019. Analysis was by a multilevel mixed effects logistic regression model, adjusting characteristics of cancer, patient and county. Results: Among eligible patients (n = 14,226), telemedicine services use for all provider types increased from 4.3% in pre-waiver period to 40.3% (5.2% in OP, 39.3% in OB, and 0.2% in ED) in post-waiver period. Telemedicine services use varied by primary cancer site, but was higher for those with a cancer recurrence (odds ratio [OR] 1.36, 95% confidence interval [CI] 1.16-1.60) and advanced cancer stage (OR 1.24, 95% CI 1.03-1.48). For visits to oncologists, cancer characteristics such as recurrence (OR 1.67, 95% CI 1.34-2.08), advanced stage (OR 5.52, 95% CI 4.12-7.40) and diagnosis in the last quarter in 2019 (OR 1.39, 95% CI 1.20-1.61) were associated with greater use of telemedicine. Patients of older age and minority race/ethnicity and in non-Northeast regions were less likely to use telemedicine, while women, patients with dual eligibility for Medicaid, and those living in a county with high median household income and high availability of hospital beds were more likely to use telemedicine. Conclusions: Cancer patients used telemedicine services more frequently after the waiver and their cancer characteristics were most strongly associated with that use, implying their greater need for, and benefit from, telemedicine. Disparities in telemedicine use related to individual and county-level socio-demographics and medical supply suggest health policy changes to improve equitable access to telemedicine and efficient cancer care planning.