Objectives: Determination of the relative amounts of mutans streptococcus in both saliva and plaque and to study its correlation with dental caries in children. Study Design: The study comprised of 60 children aged 3-8 years divided into 2 groups (30 children in each): Group A- Children with more than 4 carious teeth and Group B- Children without caries. Saliva and plaque was collected from children of both the groups with the help of Dentocult SM strip test kit (Orion Diagnostic). Following incubation, mutans streptococcus scores (from 0 to 3) in each individual was evaluated and compared between both the groups. Results: On comparing the two groups, mean ± SD of saliva score and plaque score was 2.40 ± 0.675 and 2.40 ± 0.621 respectively in group A, whereas it was 0.60 ± 0.498 and 0.83 ± 0.531 in children of group B showing a significant correlation ( p = < 0.001) between mutans streptococci scores in both saliva and plaque and dental caries experience. Conclusions: There is a direct and strong co-relation between the salivary and plaque mutans streptococcus counts and caries activity in children aged 3-8 years.