The Sandia Ion Beam Test System is used to conduct high heat flux tests of full scale components for fusion experiments. Heat fluxes of more than 4 kW/cm2 have been achieved with a hydrogen ion beam. The ion beam 22 cm grid set provides an adjustable width Gaussian heat flux profile which can be focused to a full width at half maximum of 13 cm. Diagnostics include an imaging radiometer, two-color pyrometers, thermocouples, strain gauges, water calorimetry, as well as surface and metallographic analysis systems. A versatile sample cooling loop provides up to 32 l/s of water at pressures up to 6.9 MPa and temperatures up to 280 °C. The pH and oxygen content of the sample cooling water can also be controlled. A large target chamber allows targets of 1 m2 and can be separately vented for target exchange without reconditioning the ion beam grid set. An RF induction ion source allows precise beam power and perveance control for different target testing requirements. Computer control is employed through a CAMAC serial highway with a menu driven operator interface. High heat flux tests have been conducted for JET, DIII-D, and CIT. Results from these tests will be shown as examples of current high heat flux testing activities.