Apolipoprotein E deficient (Apo E-/-) mice are more resistant to the development of obesity compared to C57BL/6 wild type mice. They also hold a high basal oxidative status due to the loss of antioxidant action of apolipoprotein E. Since obesity is also an inducer of inflammation, we studied the effect of high-fat diet on obesity and oxidative stress in C57BL/6 and Apo E-/- mice for 9 weeks. The results confirmed that Apo E-/- mice fed high-fat diet are more resistant to the increase of both body weight and adiposity compared to C57BL/6 mice. Despite this, Apo E-/- mice presented a higher basal oxidative stress that was enhanced by high-fat diet. Macrophage infiltration, macrophage forming crown-like structures and proinflammatory adipokines (interleukin 6 and tumor necrosis factor alpha) were all higher in adipose tissue from Apo E-/- compared to C57BL/6 mice, regardless of diet type. In conclusion, although Apo E-/- mice are more resistant to becoming obese, they develop more severe adipose tissue inflammation companied by its consequences.