1. The location of α2-adrenoceptors has been examined in slide-mounted sections of dog kidney by using labelling in vitro with [3H]rauwolscine and autoradiography. 2. [3H]Rauwolscine binding in dog kidney was of high affinity, saturable, and to a single population of sites. Stereoselectivity was observed for (−)-noradrenaline and the relative affinity of a series of competing antagonists indicated binding to α2-adrenoceptors. 3. Autoradiography of [3H]rauwolscine binding revealed localization to three areas: glomeruli, the intimal and adventitial surfaces of arcuate blood vessels and the medullary vascular bundles.