Background.The use of kidneys from non-heartbeating donors (NHB) remains controversial. An increased incidence of delayed primary function and primary nonfunction is common. We report a characteristic syndrome of transaminitis and thrombocytopenia after NHB renal transplantation, which may be predictive of graft outcome.Methods.Two case histories are presented, followed by a retrospective analysis of 38 NHB renal grafts performed at Guy's Hospital from 1988 to 1994. Changes in alanine aminotransferase (ALT) and platelet count were compared between recipients of kidneys from NHB and heartbeating donors (HB). To control for possible effects of antilymphocyte globulin (ALG), two matched control groups receiving HB kidneys with (n=32) and without (n=32) ALG were also compared.Results.ALT was elevated in 32 of 38 (84%) of NHB recipients and 19 of 64 (30%) controls (P<0.001). Mean peak ALT was 172±20 U/L in NHB and 42±6 U/L in HB kidneys (P<0.001). Use of ALG did not influence mean peak ALT. Elevated ALT predicted impaired graft function (P<0.02) and was associated with an increased length of delayed primary function (P<0.001) and risk of transplant nephrectomy (P<0.05). Thrombocytopenia (<100×109cells/L) occurred in 18 of 38 (47%) NHB recipients and in 20 of 64 (31%) controls (P<0.05). Mean nadir platelet count (×109cells/L) was 113±10 in NHB, 128±9 in HB with ALG, and 164±9 in HB without ALG (bothP<0.05 vs. NHB). Patients who underwent graft nephrectomy (n=9) had a disproportionate fall in platelet count (mean nadir, 80±11×109cell/L;P<0.05).Conclusions.Transaminitis and thrombocytopenia occur commonly after NHB kidney transplantation and are predictive of graft outcome. Recognition of these changes may assist the early management of NHB renal recipients, and also reduce investigation of “anomalous” results in this setting.