BackgroundObesity in children is a major worldwide concern that has several negative health consequences in both the short and long term. The objective of this study was to evaluate the expression level of microRNA-122 in obese Egyptian children and investigate its potential associations with insulin resistance and cardiovascular diseases. MethodsThe study included 70 obese and 30 age-matched normal-weight control children. Anthropometric measurements, systolic, and diastolic blood pressures were assessed, and quantitative real-time polymerase chain reaction was used to determine the expression of circulating microRNA-122. Pancreatic beta cell function (HOMA2-%B), insulin resistance (HOMA2-IR), and insulin sensitivity (HOMA2-%S) was assessed by the homeostasis model assessment version 2 (HOMA2). McAuley index and single-point insulin sensitivity estimator (SPISE) was used to further evaluate insulin sensitivity. Levels of serum biochemical parameters were measured. ResultsThe obese group showed significantly higher levels of microRNA-122, fasting blood glucose, triglycerides, total cholesterol, LDL, VLDL, non-HDL cholesterol, cardiac risk ratios, atherogenic coefficient, atherosclerotic index, insulin levels, HOMA2-%B, and HOMA2-IR compared to the control group. In obese children, microRNA-122 exhibited a significant negative correlation with HDL while a significant positive correlation with the cardiac risk ratio 1 and the atherogenic coefficient. MicroRNA-122 had predictive ability for insulin resistance and cardiovascular diseases risk in obese children. However, a significant decrease in HDL levels, HOMA2-%S, McAuley, and SPISE insulin sensitivity indices was found in obese children. ConclusionsModifications in blood levels of microRNA-122 in obese children may indicate a possible role in the etiology of childhood obesity and its associated consequences. As a result, it could function as a preliminary biomarker and potential indicator of further metabolic diseases.