Abstract Background According to International Society for Heart and Lung Transplantation (ISHLT) data, the 30-day survival after heart transplantation has continually improved from 84% (1979–85) to 91% (1996–2001). This has probably been achieved by better donor/recipient selection, along with improved surgical technique and immunosuppressive therapy. On the other hand, the data concerning the early causes of death after cardiac transplantation is incomplete, because in 25% of cases, an unknown cause is listed. This study investigated the incidence and causes of 30-day mortality (determined by postmortem studies) after cardiac transplantation and assessed the possibility of improvements. Methods A retrospective study of all patients who underwent heart transplantation at Papworth Hospital from 1979 to June 2001 ( n = 879) and who died within 30 days of surgery was carried out. Postmortem examination data were available for all patients. Results The mean (standard deviation) recipient and donor ages were 46 (12) and 31 (12) years, respectively. Overall, the 30-day mortality was 8.5% ( n = 75), 12.1% for the 1979 to 1985 period and 6.9% for the 1996 to 2001 period. The primary causes of death were graft failure (30.7%), acute rejection (22.7%) (1.3% for the 1996–2001 era), sepsis (18.7%) gastrointestinal problems (bowel infarction and pancreatitis; (9.3%), postoperative bleeding (6.7%), and other (12%). Conclusions Our 30-day mortality compares favorably with the data from the ISHLT registry, with great improvement in the early mortality. Acute rejection is no longer a major cause of early mortality. Further reduction may be achieved by a better protection of the donor heart against the effects of brainstem death and ischemic injuries. However, the quest to improve early outcome should not be at the expense of needy patients by being overselective.