This study aimed to evaluate the feasibility and safety of a new 6 French (6 Fr) intra-aortic balloon pumping (IABP) catheter for patients undergoing percutaneous coronary intervention (PCI). Sixty-nine consecutive patients who received a 6 Fr IABP catheter were retrospectively evaluated. Patients with height <162 cm were primary selected for the 6 Fr IABP catheter treatment because of limited balloon size (30 ml). These catheters were also used for patients for whom the femoral approach was contraindicated. The mean age of the patients was 76.9 years. The average height and body weight were 156.7 cm and 56.0 kg, respectively. The 6 Fr IABP catheters were successfully inserted in all 69 patients, including four patients treated via the brachial artery. No patient developed limb ischemia. Poor helium inflation due to kinking of the catheter shaft occurred in one patient and helium leakage in one patient. The other 67 patients were well supported, and no patient required the 6 Fr catheter to be exchanged with a larger balloon catheter. The current study demonstrates that using this novel and currently, the thinnest IABP catheter is feasible and safe for small-sized patients undergoing PCI and seems promising for reduction in vascular complications. Brachial insertion is also possible using the 6 Fr IABP catheter; this may solve access site limitations observed with existing conventional IABP catheters.