Background: With increasing incidence rate of human malignancy, it is critical to maintain an adequate oncologist workforce to meet the societal need for expected oncologic care. Methods: In January-February 2023, ASCO emailed a novel 36 item REDCap survey to 5892 U.S.-based ASCO physician members to evaluate career intentions. The survey included 2 questions from the Maslach Burnout Inventory (MBI). The survey was distributed through multiple ASCO channels in February-March 2023. Survey responses were compared to findings from a 2013 survey of 1345 oncologists by Shanafelt et al.¹ Per convention, those with high levels of emotional exhaustion and/or depersonalization were categorized as having burnout. Results: 410 eligible responses were analyzed. Demographic characteristics of oncologists in active practice (ACs) (≥ 6 hours/week) and oncologists no longer in active practice (FCs) are summarized in the Table. Most ACs reported that their total work hours (57%) and hours spent on administrative work (68%) had increased since 2019 (pre-COVID). 49% reported an increase in patient care hours. Compared to ACs surveyed in 2013, a higher percentage of ACs surveyed in 2023 reported it was “likely” or “definite” they would leave their current practice within 2 years (21% vs. 17%, p=.049) or reduce their clinical work hours in the next 12 months (22% vs 16%; p=.009). High likelihood of leaving or reducing hours were associated with burnout (p=.002 and .003, respectively). When ACs were asked to identify up to 2 major work stressors, "Staffing levels” and “Use of the electronic health record” were the most common responses (47% of responders each) with “Payer policies and interactions” close behind (42%). Among retired FCs (42%, n=33), the median retirement age was 67 [IQR: 7]. A high proportion (42%, n=14) of these oncologists indicated they retired 2-4 years earlier than planned. Among FCs who had transitioned to non-clinical roles (56%, n=46), the median age to leave clinical practice was 58 [IQR: 21]. Among oncologists who had transitioned to non-clinical roles, the top reason for leaving clinical practice before age 50 was “Lack of satisfaction with clinical practice” (35%, n=6), while for those 50 or older it was “Desire for more work flexibility” (31%, n=9). Conclusions: The proportion of oncologists who intend to reduce clinical care hours or leave their current practice has risen over the past decade and is associated with professional burnout. Dissatisfaction with the practice environment has led some oncologists to leave clinical practice and/or retire earlier than planned. These trends have implications for the adequacy of the oncologist workforce to meet the needs of patients. (1) Shanafelt et al: J Clin Oncol 32(27), 2014.