Objectives: This study evaluated the erosive-abrasive enamel and dentin loss by in vitro cycling of carbonated soft drink and toothbrushing Methods: Extracted bovine teeth (2 × 2 mm) were embedded in acrylic resin, ground flattened and polished. From each specimen, approximately 5 mm slices were re-embedded into epoxy resin. Each seventy two enamel and dentin specimens were randomly assigned to the following six groups; Group A (control group): erosion only, Group B (control group): brushing only, Group C: immediately brushing after erosion, Group D: brushing after 30 min, Group E: brushing after 60 min, Group F: brushing after 120 min. The specimens submitted to 3 alternating de- and re-mineralization cycles, including abrasion by tooth brushing. The specimens were exposure of carbonated soft drink (Coca-Cole) for 2 minutes except for group B (toothbrushing only). They were immersed in remineralization solution for 0, 30, 60 and 120 minutes, respectively. All specimens were brushed for 100 strokes with the dentifrice slurry using a V-8 cross brushing machine. This study tried to evaluate surface enamel loss by modified Knoop indentation measurement for surface loss. The surfaces micro structural changes also were investigated by SEM. Results: After these cycles, the means of surface enamel and dentin mineral wear were as follows; A (-0.091/-0.157 ㎛), B (-0.058/-0.373 ㎛), C (0.014/-0.194 ㎛), D (0.14±0.10/-0.19 ㎛), E (0.138/0.005 ㎛), F (0.213/-0.101 ㎛). The enamel loss was significant differences between the control groups and all experimental groups (p<0.05), dentin loss was significant differences between group B and groups A, C, D, E and F (p<0.05). According to the SEM images, group A of enamel specimen showed a higher degree of surface roughness than the experimental groups. Group A of dentin specimen showed the largest dentinal tubule, while group B (brushing only) and experimental groups were decreased the dentinal tubule size. Conclusion: The enamel and dentin surface loss of immediate toothbrushing after exposure of soft drink were not significant different in those of delayed toothbrushing