Electroplating selective copper oxide coatings were prepared on the surface of a rectangular absorber (alpha = 0.92 and epsilon(100)degrees C = 0.18) for Operation in conjunction with a prototype linear solar Fresnel reflecting concentrating collector. Overall heat loss coefficients (U-L) of the selectively coated absorber at temperatures up to similar to 300 degrees C, optical efficiency (eta(o)) and stagnation temperature of the concentrator-absorber system were determined experimentally. The results have been compared with those obtained from an identical black painted absorber. Thermal efficiency (eta(c)) computed from the results of U-L and eta(o) measurements at a temperature of 250 degrees C provides a value of 49% with the selectively coated absorber and 48% with the black painted absorber.