110 Background: Despite cancer treatment advances from clinical trials, the proportion of those with cancer enrolling on oncology studies remains low, due to system-, patient-, and physician-level facilitators and barriers to participation. To better understand the upstream context impacting oncologists’ consideration of trials, we studied oncology fellows’ perceptions of trial participation and preparedness for clinical research. Methods: All year 1 (Y1), Y2, & Y3 fellows taking the 2023 ASCO Medical Oncology In-Training Exam (ITE) were invited to take a post-ITE optional survey. After consent, fellows answered whether they agree, disagree or are unsure of their preparedness by their fellowship program to address key elements of practice and research and their perceived importance of trial participation after training, ranging from Very Important, Important, Moderately, Slightly, or Not Important, the latter 3 ratings aggregated and labeled as ‘less important.’ Descriptive statistics and Chi-squared tests comparing responses by fellowship year are presented. Results: Overall, 97% of fellows (2184/2231) taking the 2023 ITE participated in this study and are included in this analysis; 32% were in Y1, 37% Y2, 30% Y3. When asked ‘my fellowship training program is adequately preparing me to address the following in my future,’ nearly one in four fellows felt unsure or disagreed that their program prepared them for (a) treating patients outside of an academic medical center (Y1 24%, Y2 24%, Y3 23%) or (b) conducting clinical research (Y1 26%, Y2 26%, Y3 28%). When asked ‘how important is it to you to have the opportunity to participate in clinical trials following completion of your training,’ nearly half of oncology fellows (Y1 49%, Y2 46%, Y3 40%, p.038) felt trial participation was ‘less important.’ When considering future practice setting, two out of 3 fellows (66%) planning a non-academic practice and one of 3 fellows (33%) planning an academic practice rated trial participation as ‘less important’ (p<.0001). When compared to fellows who reporting being unsure or unprepared by their programs to conduct clinical research, those who felt adequately prepared were more likely to rate trial participation as important/very important (57% vs 49%, p=.005). Conclusions: Our findings show that value of clinical trial participation is assigned early in oncologists’ careers during fellowship training. Addressing barriers to clinical trial participation calls for multilevel interventions that include efforts to identify and augment clinical research learning needs of oncology fellows and ensuring broad exposure during fellowship to successful and efficient conduct of cancer clinical trials.