This book constitutes the refereed proceedings of the 4th International Conference on Artificial Intelligence over Infrared Images for Medical Applications, AIIIMA 2025, held as a virtual event, on November 15, 2025.The 13 full papers presented in these proceedings were carefully reviewed and selected from 23 submissions. They focus on the application of artificial intelligence in medical infrared imaging for cancer screening, cancer diagnosis, cancer risk assessment, treatment monitoring, sports injury, and pain management.