Background: Transradial approach has been considered as limitation in a percutaneous coronary intervention (PCI) of chronic total occlusion (CTO). However, with technical development, transradial approach could be an alternative to femoral approach. Therefore, we tried to evaluate the clinical efficacy of transradial approach for PCI of CTO lesions. Methods: From February 2002 to June 2004, 96 CTO lesions (76 male, mean age: 56 years old) were enrolled in the study. Most of the transradial CTO lesions were tried in ad-hoc procedures. If contralateral injections are required, ipsilateral femoral puncture were done. Biplane cine angiography, use of tapered-tip guidewire or microcatheter and See-saw technique was used with operators's discretion. Results: Success rate of CTO was not different between 2 groups (78% vs 77%, p=0.83). Other parameters were listed in the table. Conclusion: Transradial approach could be an alternative to transfemoral approach in a selected patients, although the contralateral injections were necessary in a half of the patients.