The purpose of this study was to investigate the effect of surface treatment on the bond strength between CAD/CAM zirconia and veneering ceramics. The debonding/crack initiation strengths between zirconia and veneering ceramics were measured according to ISO9693. Hundred zirconia plates, 25.0 mm × 3.0 mm × 0.5 mm, were made with three CAD/CAM zirconia blocks (2M, Korea). Fifty zirconia plates were equally divided into 5 groups, sandblasted with 70 μm alumina at 2.5 atm, and sintered with five different veneering ceramics of AD, LC, NT, VT, and ZZ. Another fifty zirconia plates were equally divided into 5 groups and five kinds of surface treatment were employed: group 1: sandblasted with 70 μm alumina at 2.5 atm (BO); group 2: sandblasted and heat-treated at 1000℃ for 10 minutes (BH); group 3: sandblasted, acid-etched with 5 wt% HF solution for 10 minutes and heat-treated(BAH); group 4: sandblasted, heat-treated and acid-etched (BHA); group 5: sandblasted, acid-etched and treated with borosilicate glass at 1100℃ for 10 minutes (BAG). The three point flexural test was performed at crosshead speed 1.5 mm/min. debonding/crack-initiation strength was calculated a ccording to I SO9693. Arithmetical a verage r oughness value, R a, o f the zirconia surface blasted at 2.5 atm with 70 μm alumina was 0.304±0.036 μm. The debonding/crack-initiation strengths between blasted zirconia and five veneering ceramics were 27.1-33.2 MPa, there were no significant differences between in each group (P>0.05). The debonding/crack-initiation strengths of the BAH and BAG groups were higher than that of the BO group, but there were no significant differences between in each group (P>0.05).