Financial institutions face a significant challenge in the fight against financial crime, highlighting the importance of effective Customer Due Diligence (CDD). In this chapter, we review the current state of the art of CDD in the context of anti-money laundering (AML) compliance and the role of customer due diligence in ensuring compliance with regulatory requirements and protecting against financial crimes. Financial institutions that adopt thorough CDD practices position themselves to not only meet regulatory demands but also to effectively recognize and reduce potential threats, allowing institutions to respond appropriately and avoid the significant repercussions that come with regulatory violations and damage to their reputation. Through comprehensive CDD strategies, financial institutions can greatly reduce their vulnerability to financial crime and adhere to mandatory regulatory standards and promote their long-term viability in an unpredictable market.