Abstract Standard, untreated, crumb rubber typically commands a low selling price, usually $0.33–0.66/kg. This low value has limited the full recovery of the rubber from waste rubber products. An emerging technology involving the surface treatment of rubber particles with chlorine gas may improve the characteristics of waste rubber so that it can be used in high-value products, which could support a higher price for treated rubber. This research identifies the two most significant end-use markets for treated rubber particles: footwear (shoe soles and components) and urethane-foam carpet underlay markets. In these major markets, research has clearly demonstrated that two categories of surface-treated rubber particles can be used easily in existing manufacturing plants and processes and has shown that the material meets or exceeds existing standards for performance, quality, and cost-effectiveness. The combined market potential of the surface modified rubber particles is estimated to be 10 8 kg/yr. The current price of the surface-treated material is estimated to be $1.10–1.43/kg, which could be economically sustained in these high-value applications. Modifying the surface of scrap tire rubber may also yield substantial energy savings. The modified scrap rubber may also contribute greatly to the use of postconsumer scrap-tire waste as a higher value material in polymer compounding. One barrier is moisture in the surface-treated rubber material (0.8–1%), which is curtailing the commercial success of surface-treated rubber particles in urethane-molded products. Further development is under way to correct that problem.