It has been recently adopted under Polish law that the determinant of death is both the brain death criterion, tantamount to the permanent and irreversible cessation of its function, and the equally valid circulatory criterion. This means that the determination of brain death is not indispensable to pronounce a person dead, because the irreversible cessation of circulation is sufficient in this respect. The purpose of this article is to present current developments in Polish law against the comparative, historical and medical background.