SANTO, Mariana
Lawyer/ Escribana (Notary Public)
Practice group
T (598) 2902 1515 ext. 253
F (598) 2902 5454

Mariana Santo, Lawyer and Notary Public, works mainly in the Litigation Department.  Her practice includes active participation in civil and commercial litigation. She holds a Master Degree in Administrative Law from Austral University of Buenos Aires (2015-2016) and a postgraduate degree in State Contracts and Public Infrastructure of same University (2014). She also has a  Master Degree in Economic Administrative Law from University of Montevideo (2005-2006). She is an interim Assistant Teacher of Public Law II of the University of the Republic. She holds a Diploma on Administrative Law from Universidad Católica of Valparaíso, Chile (2018) and from Salamanca University of Spain (2018).  She has been professor of the Introductory Session of Administrative Law, at the “Colegio de Abogados del Uruguay”.

Being Administrative Law her main area of expertise, Mariana has taken part in several tendering processes, administrative contracts and negotiations with public bodies. She also has great experience in administrative proceedings, annulling action and lawsuits against the State. She has given lectures about Public Law and published essays on numerous topics related to her area of expertise.

Also has participated in important infrastructure projects, public private partnerships, assisting clients in such area. Has vast experience in energy matters in the area of gas and electricity. 


Negligence Principle in Disciplinary Administrative Law, a review in the light of case law. FCU, 2019. School of Law, University of the Republic (Uruguay). Institute of Administrative Law.

Deliberation and Discretionality. FCU, 2018. School of Law, University of the Republic (Uruguay). Institute of Administrative Law. Sources of Administrative Law. Current view from theory and practice.

Mixed Economy Companies. School of Law, University of the Republic (Uruguay). Institute of Administrative Law. Studies on the Uruguayan Administration: developments in the administrative legal scheme. FCU,

Effects of Annulment Judgment on Third-Parties not convened to the Proceedings, with special reference to Administrative Litigation Court Judgment Number 309 dated April 26, 2006. Administrative Litigation Court: IV Academic Workshop in homage to Mr. Mariano R. Brito, Attorney-at-Law. Montevideo: FCU, 2010.

Government Liability due to Legitimate Governmental Activity. School of Law, University of the Republic (Uruguay). Institute of Administrative Law. Current Transformations of Administrative Law. Montevideo: FCU: 2010.

International Publications Recognition

  • (2019) “Rocketing profile marks her as a ‘lawyer to watch.” Legal 500

  • (2019) “Of counsel Mariana Santo has noteworthy experience advising on administrative law as well as litigating against the state”. Chambers & Partners

  • (2019) "She is impressive, really knowledgeable, super-responsible and hard-working". Chambers & Partners 

Work highlights

She advised Acciona on its participation as bidder on the tender proceedings before the Ministry of Transport and Public Works for “Proyecto Ferrocarril Central” (FCU), the most important public work project ever in Uruguay, with an estimated value of roughly one billion US dollars, and key for UPM’s projected multi-billion USD dollar investment to build a second pulp mill in Uruguay. She advised Acciona through the tender proceedings, including administrative litigation proceedings before the Administrative Litigation Court once Acciona was disqualified on the on the grounds of an alleged breach to tender documents, even though Acciona obtained the highest technical qualification and had the lowest price.

  • She advised Abal Hnos. S.A., local branch of Philip Morris International, on five administrative litigation proceedings against the Ministry of Public Health (MSP) before the Administrative Litigation Court, claiming annulment of penalties imposed by the MSP on the grounds of alleged infringements to national tobacco advertising restrictions. Abal Hnos. S.A. obtained a favorable ruling on one of the cases and awaits decision on the remaining cases, with favorable non-binding report by the State Attorney in Public Litigation.

  • Successfully represented the affiliate of the Brazilian state owned oil company Petrobras (PUDSA) and Axion Energy in two separate arbitration proceedings against Administración Nacional de Combustibles Alcoholes y Portland – ANCAP, Uruguayan state company that holds the monopoly over petroleum importation and refining.

  • Mariana is representing GNLS in a 310 million dollar case before the Uruguayan judiciary and a more than 400 million dollar case in a ICC international arbitration in Spain against OAS regarding the construction of a regasification plant in Uruguay.


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