Aims/hypothesis Obesity is associated with chronic, low-grade inflammation that has been implicated in the development of insulin resistance. This study took a proteomic approach to identify novel links between obesity, insulin resistance and the inflammatory response in type I interleukin-1 receptor knockout (IL-1RI-/-) mice which are protected against high-fat diet-induced insulin resistance. Methods IL-1RI-/- (n=7) and C57BL/6 control (n=8) mice were fed a high-fat (60% Kcal from fat) diet for 16 weeks. Insulin sensitivity was measured and proteomic analysis was performed on adipose, hepatic, and skeletal muscle tissue. Results Despite an equal weight gain, IL-1RI-/- mice had lower plasma glucose, insulin and triacylglycerol (TAG) concentrations, compared with controls, after the high-fat diet. The higher insulin sensitivity in IL-1RI-/- mice was associated with down-regulation of antioxidant proteins and proteasomes in adipose tissue and hepatic soluble epoxide hydrolase, consistent with a compromised inflammatory response. Increased glycolysis and decreased fatty acid b-oxidation, via down-regulation of pyruvate dehydrogenase kinase isoenzyme 2 and acyl-CoA thioesterase 1 respectively, may explain the increased insulin sensitivity in their muscle. Hepatic TAG was lower in IL-1RI-/- mice, probably due to a decreased flux of plasma free fatty acids to the liver, decreased hepatic fatty acid binding protein expression, and decreased lipogenesis through down-regulation of glycerol-3-phosphate dehydrogenase. Correlation analysis of proteomic and physiological biomarkers suggested that lowered cellular stress may underlie the improved insulin sensitivity in IL-1RI-/- mice. Conclusions/interpretation Disruption of the IL-1RI-mediated inflammatory response attenuated cellular oxidative stress associated with significant protection from diet-induced insulin resistance independent of obesity.