The 2010 San Fernando massacre, also known as the first massacre of San Fernando, was the mass murder of 72 undocumented immigrants by Los Zetas drug cartel in the village of El Huizachal in the municipality of San Fernando, Tamaulipas, Mexico. The 72 killed58 men and 14 womenwere mainly from Central and South America, and they were shot in the back of the head and then piled up together. The bodies were found inside a ranch on 24 August 2010 by the Mexican military after they engaged in an armed confrontation with members of a drug cartel. They received information of the place after an Ecuadorian survived a shot to the neck and face, faked his death, and then made his way out of the ranch and up to a military checkout to ask for help. There were only three survivors. Investigators later mentioned that the massacre was a result of the immigrants' refusal to work for Los Zetas, or to provide money for their release.

On 17 June 2011 the Federal Police captured dgar Huerta Montiel, alias El Wache, the major perpetrator of the mass murder. His contention was that the immigrants were killed because Los Zetas believed that they were going to be recruited by the Gulf Cartel, a rival gang. He also confessed that other bodies were put in mass graves. The immigrants were abducted from several buses, the same way others were abducted for the 2011 San Fernando massacre. The police chief that was in charge of leading the investigation of the massacre was killed by suspected members of a drug cartel.The massacre was reported as "the biggest single discovery of its kind" in the Mexican Drug War, and as "the worst known atrocity committed by Mexico's drug trafficking organization to date". The National Alliance of Latin American and Caribbean Communities asked for those responsible "to be brought to justice for such atrocity", and Amnesty International said that this "human rights crisis" is a result of "one of the most dangerous trajectories" undocumented immigrants have to cross before reaching the United States. The Mexican drug trafficking organizations often use vacant lots, ranches, and mine shafts to keep their victims and execute their rivals. Nonetheless, in 2010, this was the largest body dumping ground found since the start of Mexico's drug war.The massacre was condemned by a number of countries and international organizations. Felipe Caldern, the president of Mexico at the time, condemned the massacre and sent his condolences to the families of those affected.

San Fernando is a municipality and city located in the Mexican state of Tamaulipas. It is about 85 miles (137 km) away from Brownsville, Texas, United States. The municipality has a population of 57,220, while the city itself has a population of 29,665.