Romulo Mabanta Buenaventura Sayoc & De los Angeles traces its roots to the law firm of Gibbs, McDonough and Ozaeta which practiced law in the Philippines in 1902 when the country was still under American rule. Allison D. Gibbs was a well-known tax and corporate lawyer and Charles A. McDonough was a name in criminal law practice. In 1922, Roman A. Ozaeta became a partner of Gibbs & McDonough.

After 15 years in the public service, highlighted by two appointments to the Supreme Court, one from 1941 to 1946, and the other from 1948 to 1950, and a brief period of semi-retirement, Justice Ozaeta and his son, Herminio, reconstituted the firm and formed Ozaeta, Gibbs (Allison J., the son of Allison D. Gibbs) and Ozaeta in 1957. On account of a rule (subsequently abolished, however) that limited the partnership name to living and active partners, the Firm's name underwent several changes and evolved into its present name. The current senior partners are: Ricardo J. Romulo, Jose F. Buenaventura, and Eduardo de los Angeles. Atty. Jesus S. J. Sayoc died on June 21, 2002 and Atty. Roman Mabanta, Jr. died on August 19, 2005.

In October of 2002, the partners of the Firm celebrated the 100th anniversary of its founding with the descendants of the Gibbs family in San Francisco, California.
The Firm is the sole Philippine member of Lex Mundi, a worldwide network of about 160 independent law firms, with a combined total of more than 9,000 lawyers in all commercially significant jurisdictions throughout the world.

The Firm is composed of 75 lawyers - all of whom speak English fluently and majority of whom have received training and graduate degrees from universities abroad. The Firm offers a full range of legal services with wide experience in the fields of corporate and business laws, taxation, energy, infrastructure, securities, foreign investments, banking, finance, litigation, intellectual property and aviation and admiralty.

A broader description of each of our areas of specialization will be found hereinafter.
Partners and associates of the Firm are also active members and officers of business and civic associations such as the Makati Business Club, the Management Association of the Philippines, the American Chamber of Commerce, the Philippine-U.S. Business Council, the Philippine-U.K. Business Council, Philippine-Japan Business Council, Philippine-Korea Business Council, the Philippine-Singapore Business Council, Philippine Thailand Business Council, APEC Business Forum, Pacific Basin Economic Council, Asian Neighbors' Forum, the various chapters of the Rotary Club, as well as of professional organizations such as the Inter-Pacific Bar Association, International Business Association, Union Internationale des Avocats Asean Law Association, Tax Management Association of the Philippines, Asian Patent Attorneys Association, International Association for the Protection of Intellectual Property, Intellectual Property Association of the Philippines, the US Trademark Association and the Maritime Law Association of the Philippines.