PPARgamma is a member of the peroxisome proliferator activated receptors (PPAR) subfamily of nuclear receptors. So far two PPARgamma isoforms, PPARgamma1 and PPARgamma2, were known in mammals. We describe the structure of a novel human PPARgamma subtype, PPARgamma3. The PPARgamma3 mRNA is transcribed from a novel promoter localized 5' of exon A2. PPARgamma3 mRNA expression was restricted to adipose tissue and large intestine. Similar to human PPARgamma1 and -2, PPARy3 is activated by thiazolidinediones and prostaglandin J derivatives and binds with high affinity to a PPRE.