Law Office of Atty.Rainier R. Mamañgun Overview

Attorney Rainier R. Mamañgun is a senior partner and found of this full-service law firm based in Pasig City, Philippines. The firm provides legal services in the areas of civil and family law, labor and immigration law, corporate law, and special concerns.

The firm handles cases involving such matters as breach of contract, torts and damages, child custody, spousal and child support, domestic or inter-country adoption, annulment, reprobate of wills, visas, passports, dual-citizenship acquisition, legal briefs or legal advisories, document preparation and contract drafting, verification of titles with the Registry of Deeds, service of summons and notices from foreign courts, and notarial service. The firm also provides prosecution and defense of bigamy, anti-violence against women and children, theft and fraud, libel or oral defamation, threats and coercion, physical injuries, violation of the electronic commerce laws, and verification of pending cases in court or the prosecutor’s office, among others.

The firm works to provide representation and advice in a timely and cost-efficient manner, always with due regard to the quality of service and the specific needs of the client. 

Year this Office was Established: 2004 

Languages: Filipino, Chinese, English 
Atty. Rainier R. Mamangun, formerly a lawyer for the Philippine Department of Foreign Affairs, DFA, worked on labor, civil and criminal cases involving migrant workers and overseas Filipinos in distress. In this connection, he spearheaded various legal missions abroad to such countries as Malaysia, Indonesia, East Timor, Nepal, India, and Saudi Arabia. His work involved diplomatic representations with foreign governments as well as appearances before a foreign court. During his stint with the DFA, he was instrumental in rescuing countless victims of human smuggling and trafficking and in saving the lives of Filipinos on death row abroad.

Prior to this, he worked as a legal consultant to the National Federation of Labor Unions, NAFLU, one of the biggest labor federations in the Philippines.

In 2003, he was chosen by the Office of the Vice-President of the Philippines to be part of the Drafting Committee composed of distinguished professors of the University of the Philippines Law Faculty and representatives from concerned government agencies to draft the “Magna Carta for Seafarers”– a bill that aims to promote the welfare of millions of Filipino seafarers worldwide.

His experience in dealing with OFW concerns and involvement in the labor movement made him adept at tackling civil, criminal, immigration and labor matters.

Professional Experience

Atty. Rainier R. Mamangun is adept at handling cases in and out of court. His training with the Philippine Department of Foreign Affairs enabled him to hone his diplomatic skills which now prove crucial in his dealings and negotiations with the court and the opposition. His skills at legal drafting and the defense of existing legislation were developed through years of service at the Office for Migrant Workers Affairs and in appearances at Congressional hearings and various inter-agency meetings that dealt with law and policy formulation. He had, for instance, defended the constitutionality of the “Migrant Workers’ Act” before the Regional Trial Court and the Court of Appeals, in coordination with the Office of the Solicitor General.


• “The Policies and Laws Governing Filipino Seafarers” 
• “Comparative Analysis of the Philippine Arbitration Law and the UNCITRAL Model Law on International Commercial Arbitration (Part I)”

Bar Admission

• Philippine Bar, 2001


• Integrated Bar of the Philippines
• Fraternal Order of Utopia, Ateneo Law School
• Singles for Christ