The Sinaloa War is an ongoing internal armed conflict within the Sinaloa Cartel, centered in northwestern Mexico. The conflict began on 9 September 2024, following the transfer of Ismael "El Mayo" Zambada to United States authorities by members of the Chapitos faction. The event triggered a formal schism within the cartel and escalated into a multi-front war between the MZ/MF faction and Los Chapitos, later drawing in external cartels and regional groups.
Background
Structure of the Sinaloa Cartel
The Sinaloa Cartel has no single leader and no hierarchical chain of command. InSight Crime describes it as a network of cells that cooperate with one another, outsourcing much of its work abroad and within Mexico to local partners, and held together at the top by family ties and compadrazgo, or kinship. The International Crisis Group writes that as the organization expanded, its leadership "came to exert tight control of a federation of criminal groups and families with diverse origins and interests". The Armed Conflict Location and Event Data Project (ACLED) characterizes the arrangement as a federal structure that allows factions and allies to operate with full autonomy and in horizontal relations, without a rigid hierarchy.
That structure took shape in the late 1980s, after the collapse of the Guadalajara Cartel left a loose association of Sinaloa-rooted groups that Zambada, Guzmán and their partners consolidated under their control. Each participant continued to run his own operations, staffed largely by relatives and close associates; other traffickers and local officials came to call Zambada's group the Mayiza. Zambada, Guzmán and Juan José Esparragoza Moreno, known as "El Azul", consolidated the organization through the 1990s around strongholds in Sinaloa, Durango, and Chihuahua, the drug-producing region known as the Golden Triangle. The factions bribed and co-opted local, state and federal authorities; the most prominent case being Genaro García Luna, Mexico's secretary of public security from 2006 to 2012, convicted in the United States in 2024 of having supported the cartel for a decade in exchange for millions of dollars.
The organization had long preferred bribery to violence and alliances to battles, though it used force where it wanted to take territory. InSight Crime attributes its durability through decades of arrests and killings to this network structure, which allowed it both to replace lost members and to avoid attracting scrutiny for the violence it committed. A federation of autonomous cells depended on arbitration to hold together, and ACLED describes the surviving founders as figures whose role as mediators reduced the risk of direct conflict between the factions. Zambada, the last of them at liberty after evading arrest across a criminal career of four decades, was known for keeping a low profile and for a focus on business over violence.
Earlier internal ruptures
The alliance had broken before. In 2002, Guzmán, Zambada, and Esparragoza met the Beltrán Leyva brothers to form what became known as the Federation, or Alianza de Sangre (Blood Alliance). Marriage bound the partners together: Alfredo Beltrán Leyva married a cousin of Guzmán's, Esparragoza married Guzmán's sister-in-law, and Guzmán later married a niece of another partner, Ignacio Coronel. When Rodolfo Carrillo Fuentes of the Juárez Cartel killed two of Guzmán's operatives in 2004 and Guzmán had him assassinated, Zambada and Esparragoza took Guzmán's side, beginning a war with the Juárez organization.
The Beltrán Leyva Organization split from the cartel in 2008. Mexican authorities arrested Alfredo Beltrán Leyva on 21 January 2008; when Guzmán's son Iván Archivaldo was released from jail on a technicality soon afterward, Arturo Beltrán Leyva concluded that Guzmán had informed on his brother. Guzmán's son Édgar was killed later that year outside a shopping center in Sinaloa, and the Beltrán Leyvas allied with Los Zetas while the Sinaloa Cartel reached agreements with the Gulf Cartel and La Familia Michoacana. Guzmán, Zambada and Esparragoza remained aligned against them. The fighting spread across Sinaloa, Chihuahua and Durango and forcibly displaced hundreds of people; Mexican marines killed Arturo Beltrán Leyva in Cuernavaca in December 2009.
Guzmán's arrest in January 2016 and extradition to the United States the following year set off a further struggle, in which his lieutenant Dámaso López Núñez, known as "El Licenciado", tried to take control of the organization from Guzmán's sons. In February 2017, Zambada survived an ambush attributed to López Núñez that also targeted two of the sons. Crisis Group records 1,797 homicides in Sinaloa between January 2016 and May 2017; the Chapitos put down the revolt, and López Núñez was arrested and extradited to the United States in July 2018.
Friction between the Chapitos and the Mayiza persisted afterward. Leaked Mexican military intelligence from 2019 to 2022 recorded turf battles between armed cells of the two factions, and tensions between their leaders rose sharply after members of Zambada's family testified against Guzmán at his trial in New York in 2019. In June 2021, a group associated with the Chapitos killed a Mayiza operator known as Morgan and left a message threatening a member of the Rusos, the Mayiza's principal enforcement wing; the Rusos had broken with the Chapitos after declining to take part in the effort to free Ovidio Guzmán López in 2019. Los Chapitos and the succession
Guzmán's arrest in February 2014 prompted his sons to seek a larger role in the organization, which led to a series of disputes with the Mayiza. He was recaptured on 8 January 2016 and extradited in January 2017, and was convicted in New York in 2019 and sentenced to life imprisonment. Iván Archivaldo Guzmán Salazar, Jesús Alfredo Guzmán Salazar, Ovidio Guzmán López, and Joaquín Guzmán López inherited part of his operations and became known collectively as Los Chapitos.
From 2017, the faction acquired a virtual monopoly on drug dealing and fentanyl production in Sinaloa, before expanding into extortion, control of water distribution and the illicit tobacco and electronic-cigarette trade in Culiacán. To guard the city against rivals, it built its own communications and surveillance systems and put hundreds of local police officers on its payroll.
On 14 April 2023, the United States Department of Justice unsealed charges against all four brothers in the Southern District of New York, the Northern District of Illinois, and the District of Columbia, together with chemical suppliers, laboratory managers, money launderers and weapons traffickers. Attorney General Merrick Garland called the cartel's operation "the largest, most violent, and most prolific fentanyl trafficking operation in the world", and said it was fueled by Chinese precursor chemical and pharmaceutical companies. The department separately described the Chapitos as the more violent and aggressive faction of the cartel.
Twice before the war the faction demonstrated that it could contest the Mexican state directly. On 17 October 2019, federal forces captured Ovidio Guzmán López in Culiacán; the Chapitos besieged the city, orchestrated a prison break and kidnapped soldiers and their relatives, and López Obrador ordered him released. He was recaptured on 5 January 2023. During this process, gunmen besieged Culiacán and several other municipalities in Sinaloa, once again pressuring the government to release their leader. This ultimately failed, and Guzmán López was extradited on 16 September 2023 and charged with fentanyl trafficking.
Capture of El Mayo
On 25 July 2024, Ismael "El Mayo" Zambada was lured to a meeting organized by Joaquín Guzmán López outside Culiacán, subdued and sedated, and flown to Doña Ana County International Jetport at Santa Teresa, New Mexico, about 10 kilometers from the border, where both men were arrested on landing. In December 2025, Guzmán López admitted to taking part in the abduction. The seizure was understood within the organization as a betrayal by the Chapitos, and the Mayiza accused them of delivering Zambada to United States authorities.
Belligerents
Two of the cartel's factions fought each other:
Los Chapitos, or La Chapiza, led by the sons of Joaquín "El Chapo" Guzmán; La Mayiza, or Los Mayos, led by loyalists of Ismael "El Mayo" Zambada.
At least twenty smaller armed cells worked with them in shifting alliances. Crisis Group identifies two further factions of comparable standing operating in Sinaloa: one led by Guzmán's brother Aureliano Guzmán Loera, alias El Guano, and the remnants of the Beltrán-Leyva Organization under Fausto Isidro Meza Flores. Of the two, only Meza Flores is reported to have entered the war.
La Mayiza
La Mayiza was built by Zambada and passed after his capture to his son Ismael Zambada Sicairos, alias Mayito Flaco. In a report published in May 2025, the Armed Conflict Location and Event Data Project (ACLED) described the faction as dominating operations in Durango and the rural areas of Sinaloa, with a strong presence in Baja California, Sonora, and Zacatecas; InSight Crime places its presence on the south side of Culiacán and in the Golden Triangle. Its armed wings, previously subject to clearer lines of command, operated with greater territorial autonomy after July 2024. By 2026, Crisis Group reported that the faction had taken most of Culiacán from Los Chapitos and was dominant in the south and east of the city.
Los Rusos, identified by the United States Department of Justice as the faction's principal armed wing, controlled trafficking routes in Baja California and around San Luis Río Colorado in northwestern Sonora under Juan José Ponce Félix, alias El Ruso. A second wing, Los Rugrats, operated from Laguna Colorada in Culiacán Municipality under Carlos Alberto Páez Pereda, alias Carlitos. A third, the Fuerzas Especiales Avendaño, sustained more casualties than any other wing in the war, according to the journalist Óscar Balderas. Los Rusos had broken with Los Chapitos after refusing to join the effort to free Ovidio Guzmán López during the 2019 Culiacanazo. Grupo Flecha, La Sombreiza, Los Cazadores, and Los Ántrax have also fought on this side.
On 18 September 2025, the Office of Foreign Assets Control of the United States Department of the Treasury added the faction to its sanctions list, blocking any assets they hold in the United States and barring Americans from dealing with them. Treasury said the faction traffics fentanyl, cocaine, marijuana, heroin, and methamphetamine into the United States, and that in Rosarito it engages in kidnapping, extortion, money laundering, and the corruption of local government.
Los Chapitos
Los Chapitos is led by Iván Archivaldo Guzmán Salazar and Jesús Alfredo Guzmán Salazar, the two of Guzmán's four sons who remain at large. ACLED's May 2025 report described the faction as operating primarily in Sinaloa, with a strong presence in Culiacán Municipality and on the state's Pacific coast as well as in Sonora and Baja California.
Los Ninis remains its best-known armed wing. Defense ministry records leaked by the hacktivist group Guacamaya indicate it was formed in 2016, after Guzmán's third capture, as the security detail for his sons. Its members were aged roughly twenty to thirty-five, and it kidnapped, tortured, and killed people it regarded as threats to its leaders, among them state officials, members of rival cartels, and traffickers within the Sinaloa Cartel itself. The wing declined after the arrest of its leader Néstor Isidro Pérez Salas, alias El Nini, in November 2023.