SummaryThromboelastography is a method of choice to follow the coagulation process. It allows an accurate study of the coagulation time and may be truly considered in this respect as a photometer of coagulation. Information is available concerning qualities of the clot, which are not accessible by other methods. Yet it will not take the place of classical coagulation tests, which are indispensable to the detailed study of the other phases of the coagulation process. In the experimental field, thromboelastography is extremely helpful in the study of the physiopathology of the platelets and of the clot structure.