Introduction: Thyroid cancers are the most common malignant tumors of endocrine origin. They are classified depending on their histopathological and clinical behaviors. Papillary and follicular cancers are classified as differentiated thyroid carcinomas (DTCs). The neutrophil/lymphocyte ratio (NLR) and the monocyte to highdensity lipoprotein cholesterol ratio (MHR) have recently been shown to be powerful markers of oxidative stress and systemic inflammation, and the MHR has been revealed as a potent marker of mortality in coronary heart disease associated with coronary atherosclerosis. The aim of this study was to evaluate these markers in patients diagnosed with DTC. Material and Method: One hundred twenty-five patients newly diagnosed with DTC and a 75-member control group consisting of entirely healthy individuals were included in the study. The patient and control groups were evaluated by investigation of cholesterol and hematological parameters following 12-h fasting. Results: Significant differences were determined between the patient and control groups in terms of mean NLR (3.2±2.8 vs 2.4±1.3, respectively, p=0.013) and MHR (0.102±0.079 vs, 0.038±0.052 respectively, p<0.001) values. In the correlation analysis, positive correlation was determined between the NLR and white cell count (r=0.530, p<0.001), neutrophil count (r=0.293, p<0.001) and C reactive protein (CRP) (r=0.371, p=0.005), while negative correlation was determined between the NLR and lymphocyte count (r=-0.271, p=0.001). Conclusion: The study data show that DTCs increase systemic inflammation.