This two-volume set of LNICST 414 and 415 constitutes the refereed post-conference proceedings of the 2 nd International Conference on IoT and Big Data Technologies for Health Care, IoTCARE 2021, which took place in October 2021. Due to COVID-19 pandemic the conference was held virtually. The 79 revised full papers were carefully reviewed and selected from 165 submissions. The papers are arranged thematically as Integrating healthcare with IoT; Information fusion for the devices of IoT; AI-based internet of medical things.