This paper addresses the Caltrans’ experience with thin asphalt rubber overlays from field test sections, accelerated pavement tests and laboratory performance tests. Field and laboratory studies have evaluated the performance of asphalt rubber as thin overlays in terms of fatigue, reflective cracking, permanent deformation and moisture sensitivity. The findings have shown that thin asphalt rubber overlays, when properly designed and constructed, can provide superior performance as compared to conventional dense graded overlays. Mechanistic analysis is necessary so that the structural contribution of asphalt rubber mixes can be adequately quantified. Proper overlay thickness design must be based on fatigue testing accompanied by mechanistic analysis.