The transradial approach for percutaneous coronary intervention (PCI) is a common route, but is associated with a few local complications. Access site complications, such as hematoma, radial artery spasm, and a reduced radial pulse, are reported frequently. However, an arteriovenous fistula (AVF) in the wrist related to the procedure is extremely rare. We encountered an AVF of the wrist after a transradial coronary intervention (TRI). The patient complained of a thrill detected in his right wrist, 2 months after TRI. Color Doppler ultrasonography demonstrated an AVF with a high turbulent velocity at the site of communication that required surgical revision. This appears to be a very unusual complication related to the transradial approach for PCI.