Radial artery occlusion (RAO) is a usually silent complication of transradial approach that may prevent future transradial procedures. It is caused by intimal hyperplasia, intima-media thickening and luminal thrombosis. RAO incidence has been reported with a wide range, probably due to different catheterization protocols and diagnosis tests adopted. Since simple pulse check at the level of radial cannulation is not reliable, plethysmography and duplex ultrasound are required to assure diagnosis. Besides the relevance of other clinical and procedural factors, inadequate heparinization and occlusive hemostasis constitute the main modifiable factors associated with risk of RAO. Finally, RAO should not be regarded as an irreversible condition since ulnar artery compression may restore patency in the case of early diagnosis, and recanalization techniques have been recently proposed to allow successful recatheterization in RAO patients.