This volume constitutes the refereed and revised post-conference proceedings of the 4th IFIP TC 5 DCITDRR International Conference on Information Technology in Disaster Risk Reduction, ITDRR 2019, in Kyiv, Ukraine, in October 2019. The 17 full papers and 2 short papers presented were carefully reviewed and selected from 53 submissions. The papers focus on various aspects and challenges of coping with disaster risk reduction. The main topics include areas such as natural disasters, big data, cloud computing, Internet of Things, mobile computing, emergency management, disaster information processing, and disaster risk assessment and management.