Abstract In public health settings, where availability of genetic counseling (GC) and testing for hereditary breast and ovarian cancer is limited, telehealth could expand access to academic centers where these services are concentrated. However, little is known about the effectiveness of remote modes for ethnically diverse and low health literacy patients. Methods. From 2017-20 UCSF researchers partnered with 3 public hospitals to conduct a partially randomized preference noninferiority trial with English-, Spanish-, and Cantonese-speaking patients with strong personal and/or family history of cancer. Participants received GC in person, by phone, or via video. Pre- and post-GC telephone surveys measured study outcomes: knowledge, cancer- specific distress, decisional conflict, risk perception, and satisfaction. A subset of 23 participants was recruited for case studies (CS) to elucidate quantitative findings. CS integrated patient and counselor in-depth interviews, GC session transcripts, and survey and tracking data for a multi-dimensional understanding of each individual’s GC experience. Results. Among 23,633 family history forms collected, 1,574 patients were eligible; 1404 were reached and 708 consented. Of 394 randomized, 322 attended GC and 312 completed the final survey. After GC, mean knowledge scores increased, and cancer-specific distress and decisional conflict decreased overall. Counseling attendance varied significantly by assigned mode (75% via video at a clinic, 77% in person, and 92% by phone), but the modes yielded noninferior outcomes. Respondents overwhelmingly rated all modes as “very convenient” and satisfaction with counseling as “very high.” Compared with baseline, knowledge increased significantly regardless of mode. However, this increase was significantly less for African Americans and for those with less education (with each adjusted for the other) across all modes. Completion of genetic testing (GT) was the inverse of counseling attendance: 94% in person, 93% video, and 65% by phone. Case studies (CS) revealed the complexities of counseling public hospital patients. Phone patients valued the access despite connection issues, but phone appointments tended to be briefer, and qualitative interviews suggested that communication was less effective by phone. While many phone patients said they would not be able to access GC any other way, several felt they would get more out it in person. Importantly, GT was offered on the spot to in-person patients while some counseled by phone had second thoughts and other barriers. CS of video counseling found benefits similar to in-person GC such as use of visual cues and formation of meaningful connections. Conclusion. Our findings indicate that GC can be delivered to high-risk public hospital patients remotely by phone, video, or in-person in order to fill a gap in access to critical genetic services. Further research is needed to achieve optimal outcomes for all patients and to increase the rate of testing for those counseled by phone. Citation Format: Rena J Pasick, Susan L. Stewart, Robin Lee, Claudia Guerra, Celia Kaplan, Galen Joseph, Selina Flores, Janice Tsoh, Niharika Dixit, Miya Frick, Heather Cedermaz, Lily Wong, Amal Khoury, Brittany Campbell. Genetic counseling for high-risk public hospital patients: A randomized and preference-based trial compares delivery in person, by phone, and video [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-051.