Lethal and accompanying complications from 29 allogeneic, 8 autologous, and 1 syngeneic transplanted pts., died between 1980 and 1986 at the BMT-Center Leipzig were revisited. An important problem was that of systemic and local infections. We observed a predominance of bacterial and fungal infections within the first 3 weeks p.t., and later on a period of predominantly virus-associated infections. The most common early death (up to 3 months p.t.) was related to ICP, as a rule caused by CMV. GvHD was a common finding at autopsy, and GvHD of the bowel seems to facilitate infectious inflammations of the bowel. There was a positive correlation between severe GvHD and the occurrence of ICP. Neither of the died BMT pts. showed signs of relapse. After ABMT ICP did not occur. The lethal complications were septicaemia, local infections, relapse and haemorrhagic diathesis. A toxic effect of DMSO in 3 pts. must be taken into account. In conclusion, a rather small number of lethal factors indicates the steps in improving results of transplantation in the future.