This book constitutes the Second Diabetic Foot Ulcers Grand Challenge, DFUC 2021, which was held on September 27, 2021, in conjunction with the 24th International Conference on Medical Image Computing and Computer-Assisted Intervention, MICCAI 2021. The challenge took place virtually due to the COVID-19 pandemic.

The 6 full papers included in this book were carefully reviewed and selected from 14 submissions. There is also an overview paper on the challenge and datasets and one summary paper of DFUC 2021.