The purpose of the study was to evaluate salivary nitric oxide (NO 2+NO3) as a biomarker of dental caries in adults and to determine the correlation between salivary nitric oxide levels and DMFT index. Eighty healthy adults were divided into two groups: as caries free consisting of 20 individuals and caries active group consisting of 60 individuals. The caries active group was further divided into three subgroups based on the DMFT score (D=decayed, M=missing, F=filled, T=teeth) as follows: Group I (DMFT<3), Group II (DMFT<10) and Group III (DMFT>10), each group consisting of 20 individuals. Saliva collected was estimated for nitric oxide (NO 2+NO3) level by Griess reaction method. One-way ANOVA was used to correlate between concentration of nitric oxide (NO 2+NO3) in saliva and DMFT index in caries free and caries active groups. Results are presented as mean + standard deviation value. The mean level of nitric oxide in saliva of control group was 49.91±15.90 and that of group I, II and III were 32.10±5.91, 32.09±7.61 and 30.14±3.06 respectively. The mean level of nitric oxide (NO 2+NO3) was higher in caries free group when compared to caries active group and was statistically significant and suggests that increased NO production might contribute to lower caries incidence in adults.