Resistin is a cysteine-rich protein postulated to be a molecular link between obesity and type 2 diabetes. The aim of this study was to investigate the role of PPARγ in the regulation of resistin expression in human primary macrophages. Fluorescent real-time PCR (Taqman) analysis of resistin expression across a range of human tissues showed that resistin is highly expressed in bone marrow compared to other tissues. Taqman analysis and Western blotting showed that rosiglitazone decreased resistin expression at both the mRNA and protein levels in human primary monocyte-derived macrophages in vitro. Resistin expression was reduced by up to 80% after exposure to 100nM rosiglitazone for 96h. Bioinformatics analysis of the genomic sequence upstream of the resistin coding sequence identified several putative PPAR response elements of which one was shown to bind PPARγ using electrophoretic mobility shift assays. Our data support a direct role for PPARγ in the regulation of resistin expression.