The aim of the study was to evaluate the effects of Casein phosphopeptide amorphous calcium phosphate (GC MI Paste Plus), Novamin (Sensodyne Repair and protect Paste) and Fluoride (Colgate Maximum cavity protection) on enamel surface after pH cycling application using microhardness test.A total number of 120 specimen collected from 60 sound molars were used in this study. The teeth were sectioned in a bucco-lingual direction into mesial and distal halves using a diamond cutting disc with a low speed handpiece and water coolant. Each half was then embed in acrylic resin block using a Teflon mold while keep the enamel surface uncover. Then the microhardness of all sectioned teeth was measured using Vickers micro-hardness test as baseline and the specimen with microhardness range 240-265 VHN were selected in study. Then the specimen were immersed in demineralizing solution for 72 hrs to reproduce white spot lesion, after that microhardness of all specimen was measured again to record the demineralized mean Vickers microhardness value. The specimen were divided into three main groups according to remineralization paste used (R) where R1 represent fluoride groups, R2 represent CPP-ACP groups and R3 represent Novamin group with 40 specimen each. Each group was further divided into two subgroups according to application of pH cycle (P) where P1 application of pH cycle for two week and P2 without application of pH cycles with 20 specimens each. The remineralizing pastes were applied according to manufacturer instruction and in order to standardize the volume of applied material, each paste was inserted into an insulin syringe then 0.2 ml (20 units) of all agents was used to cover the surface of the specimens, then rubbed on specimen surface by micro brush for 5 minutes followed by application of pH cycling protocol for 14 days. Surface micro-hardness of the specimens was measured three times using Digital Display Vickers Microhardness tester and the percent of recovery was calculated.