An intermeshing counter-rotating twin screw extruder with constant root and flight diameters of the screws having L/D ratio equal to 10 has been designed, fabricated and installed for waste rubber recycling. Waste ground rubber tire (GIRT) powder procured from local market was devulcanized and mixed with 30 phr NR to give satisfactory vulcanizates properties. Further improvement in the design of the extruder with progressively increasing root diameter of the screw yielded highly encouraging results at 170degreesC and 30 rpm.