This in vitro study was designed to investigate the effect of bleaching with hydroxyapatite material on human enamel. A total of 240 intact non carious human premolars were used. Enamel blocks of uniform dimensions (4mm×4mm×3mm) were prepared. The dental blocks were randomly divided into two equal groups (n=120), according to the application of the bleaching agent. The groups were designed as follows: Group (DW) distilled water; group (HP) hydrogen peroxide; group (HA+DW) nanohydroxyapatite with distilled water and group (HA+HP) nanohydroxyapatite with hydrogen peroxide. The materials used in this study were, hydrogen peroxide bleaching agent (Opalescence extra boost 38%), nanohydroxyapatite material (nhap), mixture between hydrogen peroxide and nhap, and distilled water. Samples were evaluated for color change using Scanning Spectrophotometer, surface roughness quantitatively using profilometer, qualitatively using environmental scanning electron microscopy and assessment of elemental composition changes using Scanning Electron Microscope and Energy Dispersive X-Ray Spectroscopy (EDS). The results revealed regarding color change, there was a statistically significant difference between groups in color change. However, hydrogen peroxide bleaching agent (HP) significantly higher than all groups. Regarding surface roughness HP group showed statistically significantly highest mean Roughness. Regarding the Calcium weight loss there was a statistically significant difference between the groups as HP group showed the highest Ca wt%. Conclusion: The nanohydroxyapatite material exhibit whitening effect, so it is considered to be an attractive material for tooth bleaching. Adding nanohydroxyapatite material to peroxide bleaching agents could decrease its detrimental effect on tooth surface. The remineralizing potential of artificial saliva is limited, as it may not repair the whole tooth surface demineralization caused by bleaching agents.