This study aims to analyze the legal standing of the principle of prudence (due diligence) as an inherent legal obligation for Notaries and Land Deed Officials (Pejabat Pembuat Akta Tanah / PPAT), and to examine the legal implications arising from negligence in applying this principle in the practice of drafting authentic deeds. Furthermore, this research aims to formulate recommendations for strengthening operational standards and supervision of Notaries/PPAT within the Indonesian legal system. The research method employed is normative legal research using a statutory approach, a conceptual approach, and a case approach. The results indicate that the principle of prudence is a substantive legal obligation inherently attached to the office of Notaries and PPAT. This principle is reflected in statutory regulations, professional codes of ethics, and civil law provisions regarding the validity of authentic deeds. Negligence in applying this principle particularly in verifying identity, the legal intent of the parties, and the fulfillment of formal requirements can lead to a deed losing its authentic nature, resulting in civil, administrative, ethical, and even criminal liability. The West Jakarta District Court Decision Number 248/Pid.B/2022/PN.Jkt.Brt reaffirms that the office of Notary/PPAT does not grant legal immunity, but rather demands a high level of professional prudence and accountability. The study recommends the reinforcement of operational standards for due diligence and the enhancement of integrated supervision to prevent the abuse of authority.