The research was carried out to determine and compare the efficiency of completely transradial access (cTRA) and transfemoral access (TFA) in retrograde chronic total occlusion (CTO) percutaneous coronary intervention (PCI). The cases of retrograde chronic total occlusion (CTO) percutaneous coronary intervention usually need the dual access. The transradial method is now used more frequently in CTO PCI, and improves the safety of CTO PCI. This retrospective, observational study was carried out in a single center. Participants were patients who underwent dual-access retrograde CTO PCI from January 2017 to October 2023, categorized into two groups: cTRA (biradial access) and TFA (bifemoral, or combined radial and femoral access). All patients in the cTRA group received conventional radial access. All punctures of the femoral artery were performed without fluoroscopic or ultrasound guidance. None of the patients in the TFA group accepted any arterial closure devices. Clinical, angiographic and procedural characteristics and the occurrence of in-hospital major adverse cardiovascular events (MACE) of the cTRA and TFA procedures were recorded. This research involved 187 CTO PCI procedures with dual access, of which 88 were done using cTRA and the rest (99) were carried out through TFA. The J-CTO (Multicenter Chronic Total Occlusion Registry of Japan) score was lower in the cTRA group than TFA group (2.1± 0.6 vs 3.0± 0.8; P <0.001). The technical success (84.1% vs 82.8%; P= 0.817), procedural success (80.7% vs 79.8%; P= 0.906) and in-hospital MACE rates (5.7% vs 4.0%; P= 0.510) were the same for both groups. For a J-CTO score of 3 or higher, technical success rate was significantly lower in the cTRA group than the TFA group (58.1% vs 74.2%; P < 0.001). In the retrograde CTO PCI, the percentages of success and in-hospital MACE were similar for both cTRA and TFA. Meanwhile, cTRA may be used for simpler lesions (J-CTO score < 3) as compared to TFA.