The authors emphasise the role of the pericardium in the post-operative complications of cardiac transplantation: its role is as important as it is underestimated in its frequency, severity and the pathogenic discussions that it induces. This study, based on a retrospective analysis of 191 anatomo-clinical cases (156 autopsies and 35 retransplantations) of patients undergoing cardiac transplantation before the 1/03/1993 including macroscopic and histopathologic analysis of the pericardial lesions, histochemical analysis of the lymphocytic populations, and analysis of associated coronary and myocardial lesions. The results were classified as early or late (after the 75th postoperative day) complications. Early complications included 27 suppurating mediastino-pericarditis (13 aspergillosis and 14 bacterial), 16 autonomous non-infective pericardial complications (6 haemopericardiums, 6 organised compressive haematomas, 4 early constrictive pericarditis) and 9 lymphocytic epicarditis associated with acute myocardial rejection. Late complications included one common constrictive symphysis and 14 reactivated epicarditis associated with transplantation coronary disease (chronic rejection) with associated lymphoplasmocytic nodules and a myocardial vasculitis. These observations suggest two important conclusions: 1) the need for active diagnostic measures to detect pericardial complications in cases of cardiac transplant dysfunction in the early postoperative period with no signs of acute rejection on myocardial biopsy: the presence of epicardial lesions on biopsy should be taken into account and not just assumed to be a postoperative epiphenomenon; 2) the presence of epicarditis due to reactivated epicarditis may cause inextensible hardening of the epicardium which adds to the effects of restrictive cardiomyopathy of chronic rejection.