Same-day discharge transradial percutaneous coronary intervention (TRI) has been reported to be safe and feasible in Western countries. However, Asia has not produced any reports related to this matter. The present study explored the safety and feasibility of patients with indications for TR coronary angiography and ad hoc PCI with a same-day discharge protocol. Between October 1995 and December 2002, 660 adult patients were admitted to our hospital for ad hoc PCIs. Of these, 214 patients were discharged on the day of their PCI (group A), while the remaining 446 patients were referred for out-patient department (OPD) PCI with subsequent admission (group B). Periprocedural complications were not significantly different between the groups. There were no differences in 1-month major adverse cardiac events including death, myocardial infarction, and target vessel revascularization (1.4% versus 0.2% for groups A and B, respectively; P = 0.068). Three group A cases (1.4%) experienced peri- and post-PCI myocardial infarction and one group B case (0.2%) experienced a post-PCI myocardial infarction. No patient died or required emergency bypass surgery. In group A, 8 cases (3.7%) required cutting balloon angioplasty and 2 cases (0.9%) needed rotational atherectomy. TRI is safe and feasible on an outpatient basis. For select patients, even though PCI can carry the potential risk of subsequent cutting balloon angioplasty or rotational atherectomy, the procedure should still be considered.