Physicians have been utilizing Twitter at increasing rates since its founding in 2006. Little is known regarding US radiation oncologists’ (RO) use of Twitter. We conducted a survey to better understand RO utilization of Twitter. After IRB approval, we obtained a public list of RO on Twitter curated by one author (MSK). We emailed a 65-question online survey to these 133 individuals active within the prior month as of March 2019 using Survey Gizmo. We analyzed anonymized responses utilizing descriptive statistics. Of 133 individuals surveyed, 77 responded (58% response rate). 21% were female. Ages of respondents were: 43% 30-39, 36% 40-49, and 21% ≥ 50. 72% worked in an academic practice. Mean follower count was 1440 (SD 2421) and number of accounts followed was 712 (SD 892); no significant difference was found in the number of followers when analyzed by age group, gender, US region, or practice setting (academic vs non-academic). 31% reported using social media during cancer conferences or tumor boards. Workplace policy for social media was not statistically significant in RO academic (53%) vs non-academic setting (43%) (p = 0.4). Male RO reported using >50% of their overall social media time on professional/academic purposes, significantly more than women, (62% vs. 19%, p = 0.004). No significant difference was found between those in academic practices or non-academic practices who used >50% social media time for professional purposes (55% vs 50%, p = 0.5). Answering the question “What do you believe are the benefits to your Twitter engagement? Check all that apply” the most commonly endorsed responses were “educating myself regarding cancer research updates” 87% (67/77), “networking with colleagues in radiation oncology” 74% (57/77), and “educating myself regarding overall medical updates” 71% (55/77). 67.5% responded affirmatively to the question “Do you believe more radiation oncologists should join Twitter?” and 24.7% had “no opinion.” In response to the question “What are your fears regarding your Twitter use? Check all that apply,” responses included: “I am afraid of appearing as self-promoting” 49.4%, “I am afraid of appearing unprofessional” 41.6%, “I do not have any fears about using Twitter” 35.1%, “I am afraid of violating HIPAA” 14.3%, and “I am afraid of sharing erroneous cancer information with the public” 13.0%. Among RO active on twitter, follower counts do not vary by gender, age, or practice setting. Participants perceived both benefits and risks of Twitter engagement. The profession may benefit from further attention to engagement and representation of ROs in Twitter and other potentially influential social media contexts.Tabled 1Abstract 2977; TableStrongly Agree (%)Agree (%)Neutral (%)Disagree (%)Strongly Disagree (%)Social media can improve my clinical skills and knowledge in cancer care23521645Social media enhances my feeling of belonging to the radiation oncology community17472683Social media can be helpful for my career development31392514 Open table in a new tab