In the present work we analyze the relationship of the PPARγ2 Pro12Ala gene polymorphism with the presence of obesity and assess the association of the polymorphism with insulin levels, insulin sensitivity status, estimated using the homeostasis model assessment for insulin resistance (HOMA), and lipid levels in a representative sample of 6-to 8-year-old children. This evidence concerns the gene PPARG and obesity due to melanocortin 4 receptor deficiency.