Background: A primary aim of pediatric dentists is to repair the early demineralized enamel without intervention through remineralization. Sodium hexametaphosphate (SHMP) is a remineralizing material that has been reported to have promising results for caries management. Aim of the study: Evaluation of the remineralization potential of fluoridated toothpaste with SHMP on demineralized enamel of primary teeth. Materials and Methods: Fifty six freshly extracted anterior deciduous teeth were collected and divided into four groups regarding the concentrations of SHMP added to 400 ppm F containing tooth paste. Three groups contained (0.25%, 0.5%, 1%) respectively and a control group without SHMP. Specimens were treated with the tooth pastes and exposed to pH cycling for 5 days then a remineralizing solution for additional 2 days. Specimens were evaluated using Digital Radiographic Density Analysis at baseline, after demineralization and after remineralization. Results: Teeth treated with SHMP showed marked remineralization effect than those treated with fluoride alone. Increasing the concentration of SHMP from 0.25, 0.5 to 1%, associated with increased the remineralizing effect. Conclusion: SHMP has a superior remineralizing effect over fluoride alone. 1% SHMP concentration added to 400F ppm toothpaste provided the best results.