The aim of this chapter is to focus on the techniques and applications of epicardial ablation. Cardiac arrhythmias, both atrial and ventricular, can often originate from subepicardial myocardial fibers. Sosa and colleagues described the method of percutaneous epicardial access into a dry pericardial space that provided extensive access to the epicardial surface for mapping and ablation. The purpose of this chapter is to discuss the indications and techniques of epicardial access and ablation. This chapter also covers the indications for epicardial access and ablation, technique of epicardial access and complications. Techniques of epicardial access are pericardial anatomy and preprocedural planning explained in this chapter. Important complications of epicardial access and ablation are right ventricle puncture, bleeding, liver, colon, stomach, epigastric artery or diaphragm damage, coronary artery damage, phrenic nerve (left) and pericarditis.