The purpose of this experiment was to determine the effects of various treatments on denture base resin to metal bond for cobalt-chromium alloy. The metal surface was treated as follows. Group 1 : Sandblasted with $50{mu}m$ aluminum oxide. Group 2 : Sandblasted with $250{mu}m$ aluminum oxide. Group 3 : Sandblasted with $250{mu}m$ aluminum oxide and followed by silicoating. Group 4 : Electrochemically etched. Group 5 : treated with oxidizing solution. Group 6 : Beaded with $200{mu}m$ retention structure and followed by silicoating. All specimens were applied with 4-META resin and were thermocycled 1000 times at temperature of $5^{circ}C$ to $55^{circ}C$. The effects of various surface treatments on the bond strength between 4-META resin and metal interface were measured by using the universal testing machine. All specimens were observed with SEM. The results were as follows 1. The bond strength of 4-META resin were significantly higher to Co-Cr alloy. 2. The bond strength decreased in the following orders : group 6, group 3, groups 1 and 2, group 4, group 5 and there was no statistically significant difference in bond strength among groups 1 and 2.(p>0.05) 3. The bond strength of cobalt-chromium alloy to 4-META resin were not significantly different.(p>0.05) 4. The treated surface of groups 1, 2 and 3 has more fine undercut than that of groups 4 and 5 with SEM. 5. Stable adhesion can be achieved when mechanically roughened metal surface by sandblasting than treating in an electrochemical etching and an oxidizing solution with potassium manganate.