In this case report, we describe the first documented renal subcapsular hematoma following transradial cardiac catheterization. Traditionally, this occurs via a transfemoral approach for cardiac catheterization. Initially presenting with chest pain, the patient underwent a successful percutaneous coronary intervention (PCI) via radial approach. This procedure involved the placement of a drug-eluting stent in the right coronary artery via transradial access. The patient received over 8000 units of heparin during percutaneous coronary intervention to achieve an activated clotting time (ACT) of 242 seconds. However, post intervention, the patient's condition became critical, revealing a right renal subcapsular hematoma as the underlying cause of his hemodynamic instability.