The expression of growth factors was analysed by immunohistochemistry in 25 explanted human hearts with endstage cardiomyopathy obtained at the time of transplantation surgery (12 idiopathic /10 ischemic /3 valvular heart disease). The aim of this study was to assess the relation between distribution of growth factors and fibrosis and microvessel formation in the myocardium. Basic fibroblast growth factor (bFGF) was predominantly localized in the extracellular matrix, reflected by the significant correlation between morphometric area fractions of collagen type I and bFGF (R=0.6, p<0.05). In terms of cellular distribution, bFGF was strongly expressed on vascular smooth muscle cells of small intramural coronary arteries, as detected by double immunostaining with a fluorescence-conjugated antibody against smooth muscle alpha actin. Capillary endothelial cells (stained with an antibody against von Willebrand factor, vWF) showed only weak colocalization with bFGF so that the relationship between the morphometric area fractions of vWF and bFGF was even inverse (R=–0.662, p=0.0005). Similarly to bFGF, intense immunolabeling of platelet derived growth factors AA and BB (PDGFs) was observed on vascular smooth muscle cells, whereas its correlation with the vWF-staining of capillary endothelial cells was inverse (R=–0.387, p<0.025). PDGFs were not detected in the extracellular matrix. In contrast to bFGF and PDGFs, transforming growth factor–β (TGF–β) was primarily associated with vWF-positive capillary endothelial cells. The extracellular matrix contained TGF–β in areas of scarring and repair.In the failing myocardium, TGFβ is primarily expressed on the capillary endothelium, wheras PDGFs and bFGF are more associated with the vascular smooth muscle cells of intramural coronary arteries. In addition, large amounts of bFGF are bound to collagen type 1. These distinct patterns of distribution of growth factors suggest a network of feedback mechanisms involving different cell types and the extracellular matrix during ventricular remodeling.