Deep hypothermic circulatory arrest (DHCA) is a specialized surgical technique that facilitates complex cardiac repairs by enabling bloodless operating conditions through the temporary cessation of cardiopulmonary bypass (CPB) and the diversion of blood from the circulatory system into the pump. This chapter explores the evolution of DHCA since its inception in the 1970s, its development, techniques, and cerebral protection strategies associated with DHCA, highlighting its role in complex aortic and cardiac surgeries. The use of hypothermia to reduce metabolic demand and mitigate ischemic and reperfusion injuries is elucidated, alongside various methods such as nasopharyngeal temperature and electroencephalographic (EEG) monitoring for optimizing patient management during these procedures. Additionally, this chapter covers the cannulation strategies employed to initiate CPB and achieve cooling, as well as adjunctive measures to protect cerebral function. Advanced topics such as the management of acid–base balance during DHCA, alternative cerebral protection strategies like Antegrade Cerebral Perfusion (ACP) and Retrograde Cerebral Perfusion (RCP), and the nuances of rewarming and managing postoperative coagulopathies are also examined. By consolidating a wide range of clinical practices and evidence, this chapter aims to provide comprehensive insights into the intricacies of employing DHCA effectively in modern cardiothoracic surgery.