Background Recognized prognostic factors associated with increased risk of recurrence in patients (pts) with HR+, HER2- early breast cancer (EBC) are higher histologic grade, larger primary tumor size, and greater lymph node involvement. Genomic assays like Oncotype DX obtain prognostic information to indicate benefit of adjuvant therapy. The objective was to examine use of genomic assays and describe demographic, clinical, and pathological characteristics of pts tested. Methods Real-world data was drawn from the Adelphi EBC I Disease Specific Programme, a cross-sectional observational study in France, Germany, Italy, Spain, United Kingdom (UK), United States (US) and Japan. 765 consulting physicians were surveyed, including questions on use of genomic assays to assess risk of recurrence. In each country, 20-64 of the physicians also completed patient record forms from Mar-Sep 2019 for up to 8 eligible pts with HR+, HER2- EBC. Results Physicians in US (n=176), UK (n=52) and Spain (n=100) reported highest use of genomic assays to categorize patients from low to intermediate risk (US 61%; Spain 57%; UK 65%) and from intermediate to high risk of recurrence (US 64%; Spain 67%; UK 65%). Lowest use was in Japan (n=134), 13% and 20%, respectively. Oncotype DX was consistently reported as the most frequently used genomic assay to assess the risk of recurrence (see table). Patient record forms were completed for 2447 pts (98% female, mean age 59.6 years, SD 13.0). Frequency of Oncotype DX testing varied by stage, with less testing in stage III pts (stage I 26% (194/755); stage II 20% (221/1130); stage III 11% (56/505) p50 years (age ≤50 25% (161/657); age >50 18% (318/1790); p=0.0003). Similar patterns were seen across countries, and significant in Germany (p=0.0029) and Italy (pCitation Format: Jacqueline Brown, Rhys Williams, Alex Rider, Rosie Wild, Michael Method. Multi-country study of the use of genomic assays in HR+, HER2- early breast cancer and characteristics of patients tested [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS4-34.