Due to its superior safety profile and improved outcomes, trans-radial percutaneous coronary intervention (TRI) has become the preferred access in percutaneous coronary intervention (PCI) of native coronary disease. This study investigated the impact of TRI on in-hospital outcomes after PCI for coronary artery bypass graft vessels (GV-PCI). We analyzed patients who underwent GV-PCI in 2019–2022 from the Japanese nationwide registry. Patients were categorized into the TRI and trans-femoral percutaneous coronary intervention (TFI) groups. We assessed the association of TRI and in-hospital outcomes. The primary outcome was a composite of in-hospital death and major bleeding. GV-PCI was performed in 2,295 Out of 972,370 total PCI procedures. The primary outcomes occurred in 29 patients (1.3%), including 17 deaths (0.7%). Major bleeding occurred in 12 patients (0.5%), and access site bleeding in seven patients (0.3%). The TRI group (N=1,521) showed lower crude rates of the primary outcome (0.9% vs. 1.9%, p = 0.039), major bleeding (0.3% vs. 1.0%, p = 0.027), and access site bleeding (0.1% vs. 0.6%, p = 0.047) compared to the TFI group (N=774). Univariable logistic regression demonstrated a significant association of TRI with reduced primary outcome (odd ratio (OR):0.47, 95% confidence interval (CI):0.22-0.98), major bleeding (OR:0.25, 95% CI:0.07-0.80), and access site bleeding (OR:0.20, 95% CI:0.03-0.94). In the multivariable analysis, TRI was still significantly associated with a decrease in major bleeding events (OR:0.29, 95% CI:0.07-0.93). In conclusion, the use of TRI was associated with a reduction in bleeding events when referenced to TFI in the context of GV-PCI.