The first significant successes with human liver transplantation took place only in 1968, but the future for this new surgical procedure now seems assured. Its success is heavily dependent upon the provision of pathology services, in particular from clinical biochemistry. The experiences with some of the 39 British liver transplants carried out so far are recorded. At operation, a minimum of 20 technician-hours, usually outside normal working hours, is called for. In the immediate post-operative period, intensive biochemical monitoring is essential. Once the major homeostatic mechanisms are re-established after surgery, the principal biochemical investigations are those of organ function. While no specific test for rejection is yet available, the diagnosis of rejection can be made from results of the routine pathology investigations. The role of the clinical biochemistry laboratory in the management of these patients is to provide reliable results seven days a week on a range of tests. The clinical biochemist is also well placed to contribute to the solution of some of the outstanding problems of organ transplantation.