On Wednesday 17 May, a conference promoted and supported by the Association Européenne d’Avocats – European Association of Lawyers (AEA-EAL) and the General Council of the Spanish Bar took place, with Spanish and Argentine specialists on the treatment and obligations of lawyers in the prevention of money laundering and the financing of terrorism in Europe and South America, sparking a lively debate on the professional secrecy of lawyers and their defense in this matter. In Europe, according to the provisions of Directive (EU) 2015/849 on the prevention of the use of the financial system for the purpose of money laundering or terrorist financing, lawyers are obliged to take special care to ensure that the transactions we advise or carry out on behalf of our clients are not financed with illegal funds. The regulations oblige any lawyer, as an obliged entity, who becomes aware of a transaction or event, even an attempt, that may be related to money laundering, to report the situation to the corresponding Service, and not to inform the client of it (Art. 33 and 34 of the Directive). We are only exempted from this if the client comes to us to defend him in legal proceedings or if we intervene after the irregular transaction has taken place. This raises important loopholes in what is a fundamental principle of the legal profession: the maintenance of professional secrecy. This problem does not arise in Argentina, where lawyers are not yet obliged to disclose such information about their clients. Apart from the controversy as to whether this could make it easier for situations in which illegally obtained funds are laundered, this exemption respects the position of trust that any person should have the right to maintain with their lawyer, without the latter having to betray them without even informing them of this. If we look at the fact that citizens end up being confidential collaborators of the authorities, just as we are tax collectors for clients, withholders of pensions and taxes for employees, controllers of compliance with labor and tax regulations for subcontractors, among many other business obligations that have proliferated in recent years, we have the eternal debate as to whether lawyers should have this “whistleblower” function that has been attributed to us and in which, on the basis of the principle of lawyer-client trust, we feel uncomfortable. Between four animated speeches by Anna Núñez and Nielson Sanchez-Stewart, on the Spanish side, and by Marta Nercillas and Carlos Negri, on the Argentinean side, this passionate debate took place in front of more than ninety attendees from both sides of the Atlantic. The conference was, therefore, a success, and denotes a concern for these issues, which go to the very core of our principles and profession. Lawyers will continue to fight, now and always, for professional secrecy which is the main pillar of our relationship of trust with the client.