Prostitution is a crime that’s designated as a predicate crime of money laundering committed by a pimp. Pimp’s money laundering is often overlooked because it’s seen as a victimless crime with no immediate or major consequences. In this thesis’s research, 2 (two) legal issues were posed. First, a legal certainty of suspicious financial transactions as an indication of predicate crimes for pimp’s money laundering and how to apply the reversal burden proof in pimp’s money laundering. The purpose of this research is to analyse the legal certainty of financial transactions that are suspected of being linked to money laundering by pimps and to analyse the application of reversal burden proof in pimp’s money laundering. The research method used in analysing the problems in this thesis is a normative legal research method using secondary data consisting of primary, secondary, and tertiary legal materials that were analysed using a qualitative approach and concluded inductively. In the first legal issue, research results showed that the legal certainty of suspicious financial transactions as an indication of a predicate crime in money laundering committed by a pimp has been reflected through the determination of the crime of prostitution as a predicate crime of money laundering in Article 2 Paragraph (1) letter U of the PPTPPU Law and the determination of several indicators of suspicious financial transactions in the PPTPPU Law. In the second legal issue, research results showed that the reversal burden proof applied in money laundering committed by pimps was applied proportionally, limited, and balanced. Limited because the object proven by the pimp is only limited to the origin of the assets they own, and balanced means that both the pimp and the prosecutor each have the burden of proof. The conclusion is that the legal certainty of suspicious financial transactions carried out by pimp as an indication of predicate crime of money laundering has been reflected in the PPTPPU Law, but due to a lack of attention from the law enforcers in its implementation, the enforcement of legal certainty of pimp’s money laundering is still not optimal due to the strength of evidence regarding predicate crime of prostitution which is still very weak and not yet optimal.