Abstract We examined the expression of peroxisome proliferator-activated receptors (PPARs) and the role of PPARs in cytokine production in mouse bone marrow-derived mast cells (mBMMCs). mBMMCs expressed PPARβ strongly and γ slightly, but not α. Activation of mBMMCs with antigen or calcium ionophore resulted in the increased expression of PPARγ mRNA specifically. 15-Deoxy-Δ 12,14-prostaglandin J 2 (15d-PGJ 2) and troglitazone, all PPARγ ligands, attenuated the antigen-induced cytokine production by mBMMCs. Carbaprostacyclin, a PPARβ ligand, also inhibited cytokine production, whereas PPARα ligands did not. These results suggest that PPARβ and γ might be included in the negative regulation of mast cell activation.