Introduction: Obesity is a gradually more important multifactorial disease in both children and adults. Obese children and adolescents are at higher risk of becoming obese in adulthood, which is associated with an increased risk of mortality and morbidity. There is subclinical systemic inflammation in obesity. The study aimed to evaluate the hematological parameters as an indicator of inflammation in obese adolescents and to show the relationship of monocyte/HDL-cholesterol ratio, having a lipid component, with other inflammatory hematological parameters. Materials and methods: We retrospectively reviewed the medical files of 60 patients, 30 obese and 30 healthy controls, aged between 11 and 16 years, who applied to the pediatric outpatient clinic. Laboratory tests, hematological parameters, gender, age, and BMI were compared between the groups. Correlations between monocyte/HDL-cholesterol ratio and other laboratory parameters in the obese group were examined. Results: BMI, Alanine aminotransferase (ALT), C-reactive protein (CRP), triglyceride, insulin, and HOMA-IR levels of the obese adolescent group were statistically significantly higher than the control group (p0.05). There was no statistically significant relationship between monocyte/HDL-cholesterol and other inflammatory hematological rates (p>0.05). There was a positive, moderate (48.6%), and statistically significant relationship between monocyte/HDL-cholesterol and MLR (p