Characteristic features of the topography and blood supply of the atrioventricular (A-V) node were studied on 80 autopsy heart specimens of adults deceased of other than cardiovascular disease. The authors used injection methods, angioroentgenography, macro- and microscopy. They refined nodal projection and established relationships between its location and the fossa ovalis, coronary sinus orifice, the base of the septal leaflet of the tricuspid valve and cardiac parameters. New information was obtained on the structural variability of the main source of A-V node nutrition - the arteria septi fibrosi, the pathways of A-V node blood supply, and the interrelationship between various types of cardiac blood supply and nodal artery variants. This information should be taken into consideration in cardiac surgery and analyses of electrocardiographic and coronarographic findings.