BACKGROUND: The technique to evaluate left internal mammary artery (LIMA) is not well established during right transradial coronary angiography. MATERIALS AND METHODS: Following coronary angiography via right radial artery, LIMA angiography was performed using 5 French (F) Judkins JL-3.5 catheter in 110 patients (56+/-9 years [range: 46-81], 77 males). Eleven (10%) patients had grafted LIMAs. Subclavian and innominate arteries were moderately tortuous in 14 (13%) patients and aortic arches elongated and more vertically oriented in 16 (15%). The catheter, standing in the ascending aorta with its natural curve, was withdrawn slowly while being rotated clockwise to engage its tip in the proximal left subclavian artery. After the tip portion was adjusted, contrast material was injected while sphyngomanometer cuff inflation applied to the left upper arm. RESULTS: Nonselective LIMA angiography was successfully performed in 108 (98%) patients. The catheter was engaged in the subclavian artery in a mean of 11+/-8 seconds (range: 3-136) from the time when the catheter was withdrawn from the ascending aorta. The image quality of LIMA was satisfactory in 103 (95%) patients and not satisfactory in 5 (5%) in whom the catheter tip was not placed near the origin of LIMA. In ten (91%) of the 11 patients with grafted LIMA, the anastomosis site and distal coronary vessels were well visualized. There were no complications, including arterial dissection and thromboembolism. CONCLUSION: Nonselective technique using 5 F Judkins JL-3.5 catheter is easy, fast, safe and reliable for evaluating LIMA during right transradial coronary angiography.