The expression of the seven P2X receptor subunits (P2X<sub>1–7</sub>) in the rat vascular system was determined using subtype-selective antibodies. Arteries of different sizes (from arterioles to conduit vessels) from a range of vascular beds were used to give an overview of receptor expression. P2X<sub>1</sub> receptor immunoreactivity was detected in the smooth muscle layer of arteries. The relative level of P2X<sub>1</sub> receptor immunoreactivity was dependent on the size of the artery and the vascular bed; expression was highest in small and medium arteries. P2X<sub>4</sub> receptors were detected in all arteries; once again, the relative level of expression was dependent on the size of the artery and the vascular bed. P2X<sub>5</sub> receptor immunoreactivity was barely detectable in most arteries studied. P2X<sub>7</sub> receptor immunoreactivity was generally punctate and associated with the outer adventitial layer. Immunoreactivity for P2X<sub>2</sub>, P2X<sub>3</sub> and P2X<sub>6</sub> receptors was not detected in arteries. These results demonstrate that arteries express multiple P2X receptor subunits and that there is a heterogeneity in the level of expression. The properties of artery P2X receptors correspond to homomeric P2X<sub>1</sub> receptors, and the function of P2X<sub>4</sub> and P2X<sub>5</sub> receptor subunits in arteries is unclear.