This volume constitutes the proceedings of the First International Workshop on Artificial Intelligence for Biomedical Data, AIBio 2025, held in Conjunction with the European Conference on Artificial Intelligence, ECAI 2025, in Bologna, Italy, during October 25–26, 2025.The 12 full papers and 5 short papers were carefully reviewed and selected from 29 submissions. The papers have been divided into the following topical sections: AI for Disease; Data Generation and Augmentation; Multimodal Techniques; and Image Segmentation. The 4 remaining papers included in these proceedings are from the keynote speakers.