Rainier new PHOTO
Name: Rainier Mamangun
Country: Philippines
Expertise: Family Law

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Professional Biography:

Atty. Rainier R. Mamaňgun, 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, Atty. Mamaňgun 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.


Atty. Mamaňgun is a member in good standing of the Integrated Bar of the Philippines. He belongs to the pool of lawyers par excellence of the Fraternal Order of Utopia – an academic organization based at the Ateneo Law School. He renders free legal service to indigent OFWs and their families as a volunteer lawyer for the Kanlungan Centre Foundation. He is also a member of Singles for Christ – a Catholic group composed of individuals committed to living a life in Christ. He was also member of U.P. HARIBON – an organization dedicated to the protection of the environment.

Professional Experience:

Atty. Mamaňgun 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.


Atty. Mamangun’s work on “The Policies and Laws Governing Filipino Seafarers,” co-authored by Dean Merlin Magallona, was published in in 2003 in the official organ of the University of the Philippines College of Law. He likewise authored the article entitled “Comparative Analysis of the Philippine Arbitration Law and the UNCITRAL Model Law on International Commercial Arbitration (Part I)” published at Hieros Gamos.


It was at the University of the Philippines where Atty. Rainier Mamaňgun took up his bachelor’s degree in Political Science as a “Iskolar ng Bayan,” or State Scholar. He was a consistent College Scholar and University Scholar at the said University. He served as the Deputy Academic Chairman of the Fraternal Order of Utopia in SY1997-1998 at the Ateneo Law School. In high school, he graduated with honors at the Don Bosco Technical College and was the recipient of the coveted St. Dominic Savio Award for excellence in conduct. He was class valedictorian in grade school and a Leadership Awardee – a distinction given to the most promising youth leaders of the country.

Firm Overview:

Atty. Rainier R. Mamaňgun is a senior partner and founder of a full-service Philippine law firm involved in Civil Law, Family Law, Criminal Law, Labor Law, Immigration Law, Corporate Law, and special concerns.

In the general area of Civil Law, the Firm handles cases involving change of name or correction of entry in birth and marriage certificates; collection of sum of money; breach of contract; torts and damages; and ejectment, among others.

In the specific area of Family Law, the Firm handles cases involving child custody; spousal and child support; paternity suits; domestic or inter-country adoption; legal separation; annulment; declaration of nullity of marriage; recognition of foreign divorce; settlement of estate of the deceased; and reprobate of wills, among others.

In the area of Criminal Law, the Firm handles the prosecution or defense in cases of Adultery or Concubinage; Bigamy; Anti-Violence against Women & Children; Estafa or Fraud; Theft; Falsification of Documents; Libel or Oral Defamation; Threats; Coercion; Physical Injuries; Bouncing Checks; Violation of the Electronic Commerce Law, and verification of pending cases in court or the prosecutor’s office, among others.

In the area of Immigration Law, the Firm provides assistance and advice in applications for spousal or fiancée visa, Philippine passports, watchlist or hold-departure orders, and dual-citizenship acquisition; verification of derogatory records with the Bureau of Immigration; and preparation of parental travel consent affidavits, among others.

The Firm likewise attends to special concerns such as assistance in securing documentary requirements for marriage; assistance in DNA paternity tests; preparation of pre-nuptial agreements, last will and testament; demand letters, legal briefs or legal advisories; document preparation in real estate transactions; contract drafting and review; verification of titles with the Registry of Deeds; service of summons and notices from foreign courts; and notarial services.

“The passionate pursuit of legal excellence” is the Firm’s guiding theme. The same is evident in all aspects of the Firm’s dealings with its clientele, the opposition, the courts of justice, and the public in general.

The partners adhere to the tenet that as lawyers, they should, at all times, observe candor and fairness with their clients and serve them with competence, diligence, and zeal within the bounds of law. The Firm’s mission is to pursue its clients’ cause to the utmost of its abilities and, in the process, bring to realization its vision of according dignity to the legal profession and advancing the greater interest of justice.