Practice Areas

  • Labor and Litigation
  • Trademark Litigation
  • Appellate Practice

Admission to the Bar

  • Admitted, 2003


  • University of Perpetual Help of Rizal (Bachelor of Laws)
  • University of Santo Tomas (Bachelor of Arts, Major in Political Science)

Notable Clients

  • Honda Cars Philippines, Inc.
  • PLDT, Inc.
  • Optodev, Inc.

Professional Activities and Memberships

  • Member, IBP PPLM Chapter 

Mr. Ariss N. Santos is a partner in Siguion Reyna, Montecillo & Ongsiako. He joined the firm in June 2010.

Mr. Santos’ practice includes labor and litigation, trademark litigation and appellate practice

In the labor practice group, Mr. Santos handled labor disputes, both collective and individual; represented Management in certification elections, collective negotiations and deadlocks, voluntary labor arbitration and illegal dismissal cases; drafted pleadings and appeared before the Labor Arbiters, the National Labor Relations Commission, voluntary arbitrators and the National Conciliation and Mediation Board.  He has extensively advised various companies in industrial relations and personnel matters, formulation of Company policies and guidelines, personnel movement, administrative disciplinary cases, redundancy, retrenchment and closure programs, including various diverse issues as outsourcing and job contracting. He also handled corporate due diligence insofar as labor and litigation matters in various projects handled by the law firm. 

His litigation practice and experience includes handling of cases filed in courts involving land cases, criminal cases, tax refund cases, ordinary civil claims for collection and damages, preparing and drafting pleadings, appearing before the Office of the Prosecutors, the first level courts and the Regional Trial Courts. 

As trademark litigation attorney, he has handled contentious cases on trademark applications, i.e., Opposition Proceedings and Cancellation of Registration Proceedings, drafted and prepared pleadings and appeared before the Mediators, Hearing Officers and the Bureau of Legal Affairs of the Intellectual Property Office.

As appellate law practice specialist, he drafted pleadings before the higher Courts, the Regional Trial Courts, the Court of Appeals and the Supreme Court.                                              

Other Relevant Work Experience / Training

He also has considerable government experience and training.  He was law clerk at the Supreme Court and the Court of Appeals. As Law Clerk, he did extensive research on law and jurisprudence on various fields of law; specifically, political and constitutional law, labor law, civil law, mercantile or commercial law, criminal law, remedial law and legal ethics.  He drafted and prepared ponencias (decision in cases filed before the Supreme Court and the Court of Appeals) and drafted Opinions (separate, concurring and dissenting opinions) assigned by the Associate Justice.  As senior lawyer, he reviewed, edited and revised the work of junior court attorneys or law clerks.   He also advised the Associate Justice on questions of policies and assisted him in the review of decisions of other Justices.  

He also had the opportunity to work with the Department of Labor and Employment (DOLE) and gained both policy and operational knowledge and perspective of the DOLE’s workings as a government regulatory agency. He once was Legal Adviser to the Secretary of Labor and Employment and in this capacity, he advised the Secretary on various employment law and recruitment matters, policies on employment and labor litigation, various contracts involving the DOLE.  As technical and legal assistant to the Secretary, he drafted decisions on bargaining deadlocks, labor disputes over which the Secretary assumed jurisdiction on account of strike, and other voluntary arbitration cases handled by the Office of the Secretary of Labor.  He was part of the Editorial and Revision Team that revised the Handbook on Workers’ Statutory Monetary Benefits, was a member of the Panel of Experts that reviewed the draft of the Implementing Rules and Regulations of Republic Act No. 9841 or the Rights to Self Organization Law.  He was also the DOLE’s focal Person on cases filed against the Philippine Government before the Committee on Freedom of Association and the Committee on Application of Standards and Recommendations of the International Labor Organization (ILO).