BACKGROUND: Cortisol is one of the important enzymes of saliva. Control of this hormone is an effective way to adjust the glucose level in diabetic patients. AIM: The aim of this research is to compare the salivary cortisol level in type 2 diabetic patients and pre-diabetics with healthy people. METHODS: In this case-control study (2018), the unstimulated salivary samples were collected from 44 patients with type 2 diabetes, 44 pre-diabetic people (case group), and 44 healthy subjects (control group), matched for age and gender. The samples were transferred to the laboratory, and salivary cortisol level was measured using ELISA. Data were analysed using SPSS 22 and Chi 2 tests. RESULTS: The mean salivary cortisol level in type 2 diabetic patients was 3.14 ± 1.17, in pre-diabetic cases was 1.83 ± 0.68, and in healthy controls was 0.86 ± 0.43 (P < 0.001). The mean DMFT in type 2 diabetic patients was 19.6 ± 6.5, in the pre-diabetic group was 13.43 ± 4.5, and in healthy controls was 9.38 ± 3.72 (P < 0.001). CONCLUSION: With regards to the results, salivary cortisol level in type 2 diabetic patients is more than pre-diabetic people, and in pre-diabetic people is more than healthy people. Also, there was a significant relation between salivary cortisol level and DMFT index.