Aim: The aim of this study is to investigate the effect of mobile phone waves and Wi-Fi on electrolytes and oxidative stress indices of saliva. Materials and methods: A case group of 20 Wi-Fi and mobile phone users and a control group of 20 deaf people were selected. Saliva samples were obtained from both of these groups. Study variables, including the electrolytes and oxidative stress indices of saliva, were measured. The independent two-sample t-test was used to analyze the data. The statistical significance was defined at p < 0.05. Results: The mean sodium and malondialdehyde (MDA) levels in the case group were higher than in the control group. The results also showed that there was no significant difference between sodium and potassium levels (p = 0.163 and p = 0.892, respectively) and the oxidative stress of total antioxidant (TAO) and MDA (p = 0.138 and p = 0.115, respectively) in either of the two groups. However, there was a significant difference in salivary nitric oxide (NO) levels (p = 0.04) between the case and control groups. Conclusion: Electromagnetic waves affected the saliva composition to an extent that it caused a significant decrease in the NO levels of the case group. Clinical significance: Nitric oxide acts as an active radical in nonspecific defense mechanisms in the oral cavity. So, reduction of NO with mobile phone and Wi-Fi waves can cause disruption in the human defense system. These results illustrate the necessity of reducing contact with these waves.