Peroxisome proliferator-activated receptor gamma (PPAR gamma) is a ligand-activated transcription factor that was originally identified as a regulator of peroxisome proliferation and adipocyte differentiation. Emerging evidence suggests that functional PPAR gamma signaling also occurs within the hypothalamus. However, the exact distribution and identities of PPAR gamma-expressing hypothalamic cells remains under debate. The present study systematically mapped PPAR gamma mRNA expression in the adult mouse brain using in situ hybridization histochemistry. PPAR gamma mRNA was found to be expressed at high levels outside the hypothalamus including the neocortex, the olfactory bulb, the organ of the vasculosum of the lamina terminalis (VOLT), and the subfornical organ. Within the hypothalamus, PPAR gamma was present at moderate levels in the suprachiasmatic nucleus (SCh) and the ependymal of the 3rd ventricle. In all examined feeding-related hypothalamic nuclei, PPAR gamma was expressed at very low levels that were close to the limit of detection. Using qPCR techniques, we demonstrated that PPAR gamma mRNA expression was upregulated in the SCh in response to fasting. Double in situ hybridization further demonstrated that PPAR gamma was primarily expressed in neurons rather than glia. Collectively, our observations provide a comprehensive map of PPAR gamma distribution in the intact adult mouse hypothalamus.