As the global prevalence of obesity and diabetes increases, attention has been focused on revealing the exact molecular mechanisms controlling these and coexisting metabolic disturbances. Peroxisome proliferator activated receptors γ – PPAR-g – are critically important in adipose tissue function. They belong to the superfamily of ligand inducible transcription factors. Peroxisome proliferator activated receptors γ directly regulate a large number of target genes that mediate gluconeogenesis, triglicerides uptake and storage, lipolysis and adipocytokines synthesis. Their pharmacological activation decreases insulin resistance. Numerous genetic variants of PPAR-g gene have been indentified, of which Pro12 Ala polymorphism is the most prevalent. It has been shown that carriers of the proline allele are at high risk of type 2 diabetes. Knowing the biology of these receptors might therefore contribute to understand underlying patomechanisms and potential ways of treatment as far as epidemiologically relevant diseases are concerned.