Objectives: The objective of this study was to evaluate the effect of incorporation of nanocalcium phosphate into the bleaching agent on microhardness and color change of enamel. Materials and methods:30 maxillary anterior teeth were divided into 3 groups,group (1):no bleaching agent.group(2): bleached with 40% carbmide peroxide.group(3): bleached with 10% of prepared nanocalcium phosphate modified carbamide peroxide.All samples were prepared and divided into control and bleached samples with and without Calium phophate and tested for color change using spectrophotometer and Hardness was evaluated using Vickers hardness test before and after bleaching with 40% carbmide peroxide. Results: No significant change in color was observed for both groups although group(2) showed yellowish color change.Hardness showed higher results for group (3) which is bleached with prepared calcium phosphate that was confirmed by SEM and EDEX results.Conclusion:Bleaching using nanocalcium phosphate particles had the highest hardness results and as the same time improved the remineralization effect on the tooth surface.