This book constitutes extended and revised versions of a set of selected papers from the 12th International Joint Conference on Biomedical Engineering Systems and Technologies, BIOSTEC 2019, held in Prague, Czech Republic, in February 2019. The 22 revised and extended full papers presented were carefully reviewed and selected from a total of 271 submissions. The papers are organized in topical sections on biomedical electronics and devices; bioimaging; bioinformatics models, methods and algorithms; bio-inspired systems and signal processing; health informatics.