Male wistar rats fed purified diets containing 15% sunflower oil (SF) by weight, high erucic acid rapeseed oil (HEAR) or low erucic acid rapeseed oil (LEAR) for 12 weeks and subjected to a moderate treadmill running program were compared with sedentary animals fed the same diets on the basis of cardiac morphology and complete analysis of cardiac phospholipids. HEAR caused the highest incidence and number of heart lesions both in untrained and trained rats but in the latter there was a highly significant increase of the lesions. LEAR gave a higher incidence of lesions than SF in untrained rats but not in trained ones. If compared to SF, HEAR and LEAR increased cardiac diphosphatidylglycerol (DPG) and sphingomyelin (SM) content (mg/g wet tissue) and decreased phosphatidylcholines (PC) and phosphatidylethanolamines (PE) in untrained rats. Marked changes in the fatty acid pattern of these phospholipids were also observed. PE and PC in trained and untrained rats fed HEAR or LEAR contained elevated levels of C 22:5 (n-3) and C 22:6 (n-3) fatty acids whereas the C 22:4 (n-6) and C 22:6 (n-6) polyenes disappeared. Monoenes (C 18:1, C 20:1 or C 22:1) largely incorporated in DPG of rats fed the cruciferous oils. In SM levels of saturated fatty acids (C 16:0, C 18:0, C 20:0) and of n-9 monoenes (C 18:1, C 20:1, C 22:1, C 24:1) were higher in rats fed HEAR or LEAR than in those feds SF. These changes were mainly related to the high level of n-9 monoenes (oleic, eicosenoic and erucic acids) as well as to the high ratio linolenic/linoleic acid present in cruciferous oils. Physical training interacted with the effects of these dietary oils on the cardiac phospholipid composition. The relation between changes in phospholipid composition and the incidence and the number of cardiac lesions is discussed.