Thromboelastography assesses hemostasis by graphic representation of the viscoelastic changes that occur during coagulation in vitro. Its clinical application was limited until convenience and reproducibility were improved with recent technologic advances. We will describe how thromboelastography is performed with specific attention to how the parameters of measurement relate to aspects of hemostasis, review the use of thromboelastography to manage transfusion therapy during surgery, discuss how anti-platelet therapy can be monitored by a specific application of thromboelastography, and describe how this assay has been utilized as a clinical laboratory test at our institution.