The purpose of this study was to evaluate the tensile bond strengths of treated alloy surfaces for resin bonded retainers. For the experiment metal surfaces of 5 alloys were teated with sandblasting, Silicoating Rocatec, and cemented with Visio-Gem. All specimens divided into two groups. The group I specimens were treated with 24-hour immersion in $37^{circ}C$ distilled water, and group II specimens were teated with 1500 thermo-cycles from $5^{circ}C;to;55^{circ}C$. The obtained results were as follows: 1. Bond strength values showed significantly different between sandblasting group and other groups after a 24-hour immersion in $37^{circ}C$ distilled water(P<0.05). 2. All samples were fractured during thermo-cycles for sandblasting group, and bond strength values for Silicoating and Rocatec groups showed significantly different after 1500 thermo-cycles from $5^{circ}C;to;55^{circ}C$.