New long-tip catheters, one for the left and the other for the right coronary artery, were designed specifically for right transradial intervention. We utilized the overbending principle to achieve more precise control of the catheters. We also analyzed principal factors involved to determine guiding catheter support considering the anatomy of the innominate artery, ascending aorta, left and right coronary arteries. Catheter shapes were designed to exploit favorable factors to compensate for mechanically disadvantageous anatomy. The catheter for the left coronary artery has an initial loop to make use of the angle between the innominate artery and the ascending aorta to introduce the catheter to the correct position to provide strong backup support. The catheter for the right coronary artery has a unique three-dimensional curve that provides sufficient backup support and compensates for the angles between the innominate artery and the proximal portion of right coronary artery to achieve coaxial engagement. The distal portions of these catheters include long tips aiming to minimize the loss of transmitted force. The performance of these catheters was studied in 143 patients with 161 lesions. Successful engagement was achieved in 138 patients with 156 lesions (97%) and coronary intervention was successful in 136 patients with 154 lesions (99%). No major complications or coronary artery dissection occurred due to use of these catheters. This study showed the present long-tip catheters to be safe and highly effective for right transradial coronary intervention. Cathet. Cardiovasc. Intervent. 49:218-224, 2000.