An environment-friendly etching system consisting of the H2SO4-MnO2 colloid was used to investigate surface etching for acrylonitrile-butadiene-styrene (ABS) resin as a replacement for conventional chromic acid etching solutions. With the etching treatment, many small cavities appeared on the ABS surface, and the surface average roughness was increased from 40 to 388 nm. The adhesion strength between the ABS surface and the electroless copper film was improved greatly with the etching treatment. The average adhesion strength reached 1.19 kN m(-1), which is close to that of chromic acid etching treatment (1.42 kN m(-1)). The Fourier transform infrared spectra and contact angle measurements indicated that -COOH and -OH groups were formed on the ABS surface with the etching treatment, and the density of the groups on the surface increased with the etching time. The X-ray photoelectron spectroscopy results also demonstrated that C=C bonds on the surface of ABS resin were oxidized to carboxylic acids in the etching process, but the C N bonds of acrylonitrile were not oxidized. The H2SO4-MnO2 colloid is an effective and environment-friendly surface etchant for ABS surface etching. (C) 2009 The Electrochemical Society. [DOI:10.1149/1.3231137] All rights reserved.