53 Background: The COVID-19 pandemic propelled a rapid shift to telemedicine use, including patients with advanced cancers needing palliative care (PC). Yet, little is known about disparities in telemedicine use for PC. We leveraged population-based data to examine the trend and factors associated with telemedicine use for PC among Medicare beneficiaries diagnosed with advanced cancers during the onset of COVID-19 pandemic. Methods: We identified patients aged ≥65.5 years diagnosed with advanced-stage breast, colorectal, non-small cell lung (NSCL), small cell lung (SCL), pancreas, and prostate cancers in 2015-2019 from the SEER-Medicare data. We included those with continuous fee-for-service coverage and had any PC claims from diagnosis to death, hospice admission, or by 12/31/2020 (whichever came first). Telemedicine was identified using procedure codes, modifiers, and place of service codes on PC claims. We described the percent of PC recipients using telemedicine each quarter in 2019-2020. Multivariable logistic models assessed patient and provider characteristics associated with telemedicine use among PC recipients in 2020. Results: Telemedicine use for PC was 0.24% to 0.48% across 4 quarters in 2019, which increased to 16.3% in Q1 and stabilized at about 30% in Q2-Q4 in 2020. Among 2,945 PC recipients in 2020, 22.5% used telemedicine. Older patients (75-84 years and 85+ years) were 4.4 percentage points (ppts) and 8.6 ppts (p-values<0.05) less likely than patients ages 65-74 years to use telemedicine. Patients who were female (4.4 ppts), residing in higher socioeconomic status areas (Yost Quintile 5 vs 1: 7.7 ppts), treated by female providers (4.1 ppts), in hospital system (3.7 ppts vs. individual physician office) and organizations with hospice and palliative care specialists (8.9 ppts) were more likely to use telemedicine for PC (all p-values<0.05). (Table). Conclusions: Telemedicine use for PC surged during the onset of the COVID-19 pandemic, with considerable disparities by patient sociodemographic and provider characteristics. These disparities suggest potential barriers related to patients’ technology literacy and internet access, provider awareness, and healthcare organization resources. Future mixed-method studies need to elucidate these barriers to design interventions at patient, provider, and system levels to ensure effective PC delivery. Selected factors associated with telemedicine use for palliative care. Absolute Probability Difference (95%CI) Age group (ref: 65-74) 75-84 -4.4 (-7.6, -1.2) 85+ -8.6 (-13.4, -3.7) Female (ref: Male) 4.4 (0.9, 7.9) Yost quintile (ref : Q1-Q2) Q3-Q4 2.2 (-1.7, 6.1) Q5 7.7 (3.3, 12.1) Hospital system (ref: Individual physician office) 3.7 (0.6, 6.7) Provider: Female (ref: Male) 4.1 (0.7, 7.5) Organization with hospice and palliative care specialists 8.9 (5.4, 12.4)