We have used scanning tunneling microscopy to observe the thermal roughening transition at the Ag(115) surface. For this purpose, a scanner and crystal assembly was employed that minimizes the lateral thermal drift of our microscope. Images were taken from room temperature, where the surface was smooth, up to 260 °C, where the surface is in the rough state. The topographs vividly demonstrate how the stepped metal surface goes through its roughening transition by the proliferation of kinks in the step edges. The roughening temperature of Ag(115), T R , is estimated to be 78±20 °C.