Background This study aimed to investigate the efficacy of three remineralizing agents on dental erosion in primary teeth. Methods Forty primary molars were randomly divided into four groups (n = 10 each): self-assembling peptide (P11-4), casein phosphopeptide-amorphous calcium fluoride phosphate (CPP-ACFP), sodium fluoride (NaF) and artificial saliva (AS; control). The erosion-like formation was created by immersing the samples in citric acid (4 x 2 min, pH 2.3) and AS (4 x 2 h, pH 7). The eroded samples were then treated with remineralizing agents and subjected to further erosion consisting of 15 cycles (3x/8-h interval) of immersion in citric acid and AS for 6 s each. Alterations in the mineral content and morphology of the samples were quantified using a microhardness tester and atomic force microscope. Results All agents had a significant remineralization effect on eroded primary tooth enamel. After further erosive challenge, enamel loss in the CPP-ACFP group was found to be significantly lower than in all other groups, and no significant difference was found between the P11-4 and NaF groups. Conclusions This study showed that all tested materials had remineralization ability, and CPP-ACFP had a superior effect in inhibiting enamel loss due to dental erosion in primary teeth. (c) 2022 Australian Dental Association.