Childhood obesity and its related comorbidities are increasingly recognised in children, predisposing them to early cardiovascular disease and metabolic syndrome. The objective of the study was to investigate markers of metabolism, inflammation and haemostasis in a group of Italian obese children and adolescents. Fifty-nine obese and 40 non-obese subjects were recruited. Fasting glucose and insulin, total cholesterol, HDL and LDL cholesterol, triglycerides, high-sensitivity C-reactive protein (hsCRP), tumour necrosis factor alpha (TNF-α), and adiponectin were measured. Hypercoagulability was assessed by measuring the circulating levels of thrombin-antithrombin complex (TAT), D: -dimer, fibrinogen, plasminogen activator inhibitor 1 (PAI-1) and von Willebrand Factor (vWF). A significant degree of insulin resistance was present in obese subjects compared with controls (p < 0.0001). The obese showed higher levels of total cholesterol, LDL cholesterol and triglycerides, and lower levels of HDL cholesterol than controls (p < 0.0001). Circulating levels of hsCRP and TNF-α were significantly higher in obese than in controls while serum adiponectin levels were significantly lower in obese than non-obese subjects (p < 0.001; p = 0.031; p < 0.0001, respectively). vWF, TAT, D-dimer, fibrinogen and PAI-1 levels were significant higher in obese subjects compared with control group (p = 0.02; p < 0.0001; p = 0.0037; p < 0.0001; p = 0.017, respectively). In conclusion, our results suggest that childhood obesity per se is associated with a proinflammatory and prothrombotic state.