Guillermo Mercado Romero is a Mexican politician who served as the Governor of Baja California Sur from 1993 to 1999. He is a member of the Institutional Revolutionary Party (PRI).
Mercado left office in 1999. In early 2001, Mercado and eighteen other former Mexican government officials were charged with diverting approximately $55 million in public funding. Mercado was indicted for two charges: Mercado's gubernatorial administration was accused of purchasing airline tickets for official government travel through a travel agency owned by his wife and daughter. Second, Mercado was also charged with improperly transferring ownership of public land to a private research institute during his tenure as governor.
Romero's wife, Maria Concepcion Casas de Mercado, owned a condo in San Diego, California, which she sold in January 2001 for $330,000. She then purchased a new home in El Cajon, California, in February 2001, just one month later, for $188,000. In June 2001, U.S. immigration agents questioned Mercado at his home in El Cajon to determine his legal status. Mercado showed the investigators a valid pilot's license and Social Security card as proof that he was in the United States legally. Mercado also had a visa, which allows Mexicans living near the U.S. border o travel up to 25 miles inside the U.S. for up to three days.