This book presents selected papers from the 20th International Conference on Intelligent Information Hiding and Multimedia Signal Processing, in conjunction with the 19th ISME 2024, held on October 4–6, 2024, in Matsue, Japan. It is divided into two volumes and discusses latest research outcomes in the field of information technology (IT) including but not limited to information hiding, multimedia signal processing, big data, data mining, bioinformatics, database, industrial and internet of things, and their applications.