Background: Gender disparities exist in medicine, including academic and medical society leadership, journal editorial boards, and research teams. Women are also underrepresented in clinical trial leadership and authorship, with one study reporting fewer than 10% female corresponding authors for randomized clinical trials in GI Oncology, GU oncology, and Hematology. Clinical trial leadership, subsequent podium presentations and authorship have downstream effects on promotion, reputation, and funding opportunities. We examined the gender of speakers in scientific sessions at the ASCO Annual Meeting (AM) and Gastrointestinal Symposium (ASCO GI) from 2019-2023. Methods: We examined speaker gender, role (session chair, abstract presenter, abstract discussant), speaker region (Asia, Europe, N. America), and presentation topic (colorectal cancer or non-colorectal cancer) for the ASCO AM GI scientific sessions and ASCO GI from 2019-2023. For the ASCO AM, we included GI oral abstracts and plenary sessions; for ASCO GI we included oral and rapid abstracts. Self-identified gender was not available; therefore, gender was assigned by physical appearance via ASCO video or institutional websites. Statistical analyses were performed using the two-proportions z-test with a p value <0.05 considered statistically significant. Results: 208 scientific abstracts were reviewed across both meetings over 5 years. There was a statistically significant difference in the % of men vs. women as abstract presenters (77% vs 23%, p <0.001). This did not differ when looking at ASCO and ASCO GI separately (ASCO 76% vs 24%, ASCO GI 78% vs 22%, p <0.001 for both) and was observed across all 5 years. Similarly, there was a predominance of men as abstract presenters regardless of speaker region (Asia 93%, Europe 74%, N. America 67%, p<0.001 for all) and presentation topic (CRC 76% vs 24%, non-CRC 78% vs. 22%; p <0.001 for both). The percent of men as repeat presenters for scientific abstracts was statistically higher than women (84% vs 16%, p <0.001). Importantly, there was no difference in men vs. women in the invited chair/discussant roles (51% vs 49%, p = 0.89). Conclusions: Our analysis of 5 years of scientific sessions for ASCO and ASCO GI shows a stark difference in the proportion of men vs women as abstract presenters regardless of presentation topic, region of presenter, and meeting year. Our data highlight the need for all trial sponsors to be more intentional in the selection of principal investigators and lead authors as these opportunities are critical to the promotion of women in GI Oncology and to diversifying approaches to clinical trial design and access. Our data is limited by how gender was assigned (i.e., not self-reported). Lastly, we commend ASCO on their efforts to ensure gender equity among the roles that are within their control, and we advocate for them to consider opportunities for self-identification of gender in their membership directory.