Abstract Introduction/Objective Social media is often used to disseminate new information and as a teaching tool that reaches a broad audience. When practice-changing data about HER2-Low metastatic breast cancer (MBC) emerged in 2022, ASCP developed CME/CMLE Twitter chats and Tweetorials to educate pathologists and laboratory professionals about how these updates will impact the diagnosis and care of patients with HER2-Low MBC. These activities were funded by educational grants from AstraZeneca and Daiichi Sankyo, Inc. Methods/Case Report Working with faculty who were active on Twitter, ASCP organized Twitter chats and Tweetorials to increase awareness about HER2-Low MBC and address how these changes will impact clinical care. A Twitter chat is a live, interactive Tweet-based discussion held on Twitter. Also called Tweet chats, these events run for 1 hr and use hashtags to keep the discussion organized. A Tweetorial is a combination of threaded Tweets that teach about a specific topic. Activities were certified for continuing education credit and were designed to be short, practical, and relevant for pathologists and laboratory professionals. Results (if a Case Study enter NA) In 2022 and 2023, ASCP used the hashtag #HER2Low to organize Twitter chats and Tweetorials. Each chat had four faculty members responding to 6-8 questions and averaged 2.2 million impressions (an impression is the # of times a Tweet is served in a timeline or search result). Faculty covered the challenges differentiating an IHC score of 0 vs 1+, the emerging use of digital pathology, ways to improve reporting, and other challenges with IHC scoring. Tweets may be amplified by Retweets (a re-posting of a Tweet), so a Tweet sent by a faculty member often reached over 1,000 views. Tweetorials had polling questions, text, images, videos, and links to journal articles. Each Tweetorial achieved over 1,400 views and over 535,000 impressions during its first week. Collectively, the Twitter Chats and Tweetorials led to over 1,050 CME/CMLE certificates. Conclusion Twitter is an evolving platform that is actively used by pathologists (see #PathTwitter) and laboratory professionals to share knowledge to a broad audience and foster a community of learning. Since content posted on Twitter remains enduring and searchable, people may find old Tweets and see which topics achieved high impressions. When spreading education on new practice-changing topics like HER2-Low breast cancer, Twitter can be an effective platform for broad content dissemination.