Purpose: To evaluate the effect of Bee Propolis on salivary Streptococcus mutans count and dental caries in rats. Materials and Methods: Thirty-six albino rats weaned atage of 19 days free from indigenous pathogens were infected by Streptococcus mutans. At the age of 25 days, rats were randomly divided into: 1-received laboratory standard rat ration blended with 10% propolis and 25% cariogenic diet (Molasis), 2-received laboratory standard rat ration blended with 10% propolis,3-received laboratory standard rat ration.RESULT. After the expiremental period the result show that propolis extracts did not show major effects on the viability of mutans streptococci count. However reduce the incidence and severity of dental caries even in present of cariogenic diet. Conclution. Effect of propolis on streptococcusmutans count and dental caries was significant even in the presence of high cariogenic challenges.