In 141 human hearts by means of coronary angiography post mortem 72 (51.1%) were found with bifurcation and 63 (44.7%) with trifurcation of the left coronary artery. In 6 hearts there was a fourfold division of the left main coronary artery. The supplying areas of the trifurcation branch was located in the left anterior or lateral ventricular wall. Its size varied in a wide range. Partly it belonged to the supplying areas of the anterior descending, partly to the left circumflex branch.