Objective. To evaluate the effect of air abrasion with different particles of different sizes and forms on the shear bond strength of adhesive resin cement to zirconia core. Material and methods. Sixty zirconia core disks were produced and sintered. The specimens were divided into six equal groups for application of air abrasion procedures. The surfaces of the specimens were treated with one of five air abrasion particles: 30 mm silica-coated aluminum oxide particles; 1-3 mm synthetic diamond particles; 110 mu m aluminum oxide particles; 30-50 mm synthetic diamond particles; and 60-80 mu m cubic boron nitride particles. The remaining 10 specimens were untreated and served as controls. Composite resin disks were cemented to each of the zirconia core specimens. All specimens were stored in distilled water at 37 degrees C for 24 h and thermocycled for 6000 cycles. The shear bond strength was measured using a universal testing machine at a crosshead speed of 1 mm/min. Data were statistically analyzed by one-way ANOVA with Tamhane tests (alpha = 0.05). The effect of the air abrasion procedures was examined using scanning electron microscopy. Results. Air abrasion with different materials affected the bond strength (P < 0.001). The highest bond strengths were obtained by air abrasion with 30-50 mu m synthetic diamond particles; the lowest bond strengths were obtained in the control group (P < 0.001). Conclusion. Air abrasion with 30-50 mu m synthetic diamond particles, 60-80 mu m cubic boron nitride particles and 110 mu m aluminum oxide particles showed higher bond strength values than other methods.