This paper reviews the legal rules that govern the way surgeons deal with human tissues during the course of diagnosing and treating their patients. The topic is dominated by the Human Tissue Act 2004, which was enacted in September 2006; thus, the article applies specifically only to England, Wales and Northern Ireland, since Scotland has separate legislation (Human Tissue (Scotland) Act 2006). Although the Human Tissue Act 2004 was built largely upon a plethora of legal principles that were developed throughout the Commonwealth and in the US, some of the principles underlying it will be equally familiar and applicable to surgeons across the world. Much everyday clinical activity falls outside the remit of the Act, and depends both upon other statutes, and on common law rules, principally those relating to consent.