Background: Blood group system and the ability to taste phenylthiocarbamide (PTC) are the most studied traits in human genetics which have been extensively used in describing genetic variations among human populations around the world that may had an effect on dental caries. The aims of present study were to investigate the caries experience among students with different bitter taste threshold in relation to blood type. Materials and Methods: The sample of present study includes dental students female aged19-21 years. The diagnosis of dental caries was done according to the criteria of Manjia et al, 1989 recording decayed lesion by severity (D1-4) MFS. Furthermore, bitter taste sensitivity was measured according to PTC (phenylthiocarbamide) test while concerning blood types, depending on the identity student’s. Statistical analysis that used in this study can be classified into two categories: Descriptive Analysis and second Inferential analysis (Levene test, One-way Analysis of Variance). Results: The data of present study demonstrated that the differences in caries experience among different bitter taste threshold were found statistically not significant although the higher mean value for the higher grades of caries severity (D2-3) were among medium taster students while the non-taster group had the higher mean value of D1. Concerning difference in caries experiences among students with different bitter taste threshold for blood types were not significant in spite of grade D1 was found higher among non –taster A, AB blood type students while for O blood type students were found within super taster. While grade D4 severity was found higher with medium taster among students with A, AB blood types while found higher with super taster among students with O type as grades D4 were absent among students with B blood type. Conclusion: Bitter taste perception which identified according to ptc test has some effect on dental caries experience and were found different for different blood type
