The aims of this study were to compare nitric oxide (NO) levels in stimulated whole saliva from individuals with and without generalized chronic periodontitis (GCP), and to evaluate correlations between these levels with a clinical diagnostic parameter. According to specific criteria, 30 individuals were divided into three groups: one comprising individuals without periodontitis (GC), a second comprising individuals with moderate GCP (GM), and a third comprising individuals with advanced GCP (GA). Samples were collected and NO levels measured. NO in the GCP group (GM: 7.78 卻 GA: 15.79 卩 was higher than in the GC group (5.86 卩. NO levels in the GA group were significantly higher (P < 0.0001) than in the GC group, and could also differentiate (P < 0.0001) the moderate and advanced forms of the disease. In addition, positive correlations between NO level and the number of teeth with a probing depth of = 4 mm (r = 0.54) and = 7 mm (r = 0.68) were observed. In conclusion, NO levels are elevated in individuals with GPC and are correlated with a periodontal clinical parameter. These results reveal that this form of periodontal disease and its severity are related to salivary nitrite concentration, indicating that NO may serve as a potential biological marker for detection and/or monitoring of GCP.