MMBU Challenge

​About the Challenge

​The MMBU Challenge, run out of the Stanford Medical AI and Computer Vision Lab, evaluates models through open-ended VQA on the Massive Multimodal Biomedical Understanding Benchmark (MMBU), an expert-curated benchmark of biomedical images.

​Evaluation

​Submissions are scored both on their answers and on the biomedical context surrounding each image — including modality, specimen, anatomy, and preparation.

​Tracks

​Three tracks cover frontier models, medically adapted models, and efficient models under 4B active parameters, allowing both large labs and small teams to compete on ground suited to them.

​Resources & Prizes

​Teams receive a public development set, weekly office hours with the organizers, special credits from Anthropic and GXL, and cash prizes. The top entry in each track will also be invited to contribute to the MMBU Challenge technical report.

​The MMBU Challenge is supported by Stanford AI Lab, Anthropic, GXL, Highlanders, and Biohub.

​Registration

​Registration will be open until 9/30, and acceptance notifications as well as credits and further instructions will be sent out shortly after. The competition will run until the end of 2026 (12/31).

​Rules and Restrictions

​All rules per track are listed in the challenge brief on the MMBU website. Be sure to check them out and clarify before beginning or registering for the challenge.

​Need more information? Visit the website here, and check out the Challenge Brief here!