Romulo O'Farrill Sr., a Mexico City industrialist and founder of one of Mexico's most influential communications empires, died Thursday of cardiac arrest at his home here. He was 84.

Mr. O'Farrill was president and general director of Novedades Editores, which publishes the business-oriented Mexico City daily Novedades, the English language News, five dailies in provincial cities, and 30 monthly and weekly magazines, and which operates leading Mexico City television and radio stations.

Born in Puebla, where he served as mayor in 1928, he started in business as an auto mechanic. He then became a race driver and later went into assembling and distributing cars in Mexico. In 1948, he acquired his first interest in what became the Novedades empire.

Known locally as "Don Romulo," he became a "close and respected friend of all presidents of Mexico in the past 50 years," News columnist David Amato wrote.

After World War II, Mr. O'Farrill worked for the development of the Pan American Highway. He founded the Mexican Highway Association and the Regional Highway Association, which prompted construction of thousands of miles of highways in Mexico.

In 1955, he lost a leg as a result of a traffic accident in Switzerland and subsequently founded the Mexican Rehabilitation Institution, which became a model for similar organizations for the disabled in other Latin American countries.

A pioneer of television in Mexico, Mr. O'Farrill launched the Televisa network in 1955. The network now has four Mexico City channels and an interest in Spanish language television outlets in the U.S. He also owned a radio station.

Novedades, his Mexico City daily, has a circulation of more than 112,000.

Mr. O'Farrill is survived by a son, Romulo Jr., vice president of Novedades Editores, who succeeds his father as chief officer.