29 female and 22 male wild boars aged between 3 and 70 months were studied gross-anatomically and microscopic-anatomically considering heart, kidneys and adrenal glands. Concerning the body weight no significant sex-differences were found between male (average weight 47,13 kg) and female (average weight 40,56 kg) piglets. Absolute and relative kidney weight in male piglets is higher (98,37 g respectively 0,42 %) than in female piglets (71,42 g respectively 0,36 %). The relative kidney weight decreases with age. On the other hand, the relative weight of adrenal glands increases with age and shows no sex differences. Contrary to the domestic pig the volume of myocyte-nuclei of the left ventricle-wall is very high (wild boar 127-136 µm3 ; domestic pig 81-117 µm3). Age and sex differences were not found. Compared with the domestic pig, the intramyocardial connective tissue content is very low (0,22-1,12 %). It increases with age. The size of the glomeruli (diameter 94-114-µm), the density (1,61-3,41 %) and the number of the glomeruli (1,53-3,54 / mm2) as well as the nuclei-volume of the zona-glomerulosa-cells (53,74-61,41 µm3) correspond with the domestic pig (61,69 µm3). The lower relative kidney weight in the domestic pig (wild boar 0,26-0,42 %), the distinctly lower relative weight of the adrenal glands (wild boar 0,0125-0,0175 %; domestic pig about 0,00242 %), lower volumes of the myocyte nuclei, very high intramyocardial connective tissue content and a higher part of glomeruli in the renal cortex of the domestic pig were discussed as changes due to domestication. Referring to our gross-anatomical and microscopic-anatomical studies the wild boar is relative unsusceptible to hypertension and stress and has a strong cardio-vascular-system. By comparison the heart of the domestic swine shows obvious disadvantageous changes due to domestication.