It is considered that caries incidence might be low in subjects with high salivary Nitric Oxide (NO) levels. Thus the objective of the present study was to determine the levels of nitric oxide in saliva of children with Rampant Caries (RC) and Early Childhood Caries (ECC). A total of 120 children were divided into 4 groups of 30 each belonging to two age groups of 6-12 yrs and 71 months or less respectively. Children between the age of 6-12 yrs were either with RC or their control and children between the age of 71months or less were either with ECC or their control respectively. The study and control subjects were divided equally. Oral health status was recorded followed by unstimulated salivary flow rate estimation. Estimation of salivary nitric oxide was measured by the concentration of its stable metabolite nitrite using Classical Griess Reaction. The mean nitrite levels of both the control groups were much higher when compared with the study groups, which was statistically very highly significant.