Los Guerreros WWE
In WCW: On the March 9, 1998 edition of Nitro, Guerrero's nephew Chavo Guerrero lost to Booker in a match. After the match, Guerrero suplexed Chavo to teach him a lesson. On the March 12 edition of Thunder, he defeated his nephew Chavo in a match and forced him to become his "slave." At Uncensored 1998, Chavo was forced to support Guerrero in the opening match of the pay-per-view where Guerrero faced Booker T for Booker's WCW World Television Championship. Guerrero lost the match after receiving a missile dropkick. Guerrero and Chavo began a feud with Último Dragón. Chavo lost to Dragón at Spring Stampede 1998. At Slamboree 1998, Guerrero defeated Dragón despite interference from Chavo. After the match, Chavo kissed Eddie and then started showing craziness. At The Great American Bash 1998, Chavo got an upset victory over Guerrero. The two faced each other in a Hair vs. Hair match at Bash at the Beach 1998 which Guerrero won. Continuing to show his crazy behavior Chavo would shave his own head while Guerrero looked on in disbelief. Guerrero saved Chavo from beatings by Stevie Ray and it seemed that he would align with Chavo but he wanted his release.
In WWE: On August 1, 2002 Guerrero and Chris Benoit began to wrestle exclusively for WWE's SmackDown! brand. With Benoit starting to focus on Kurt Angle, Guerrero aligned himself with his nephew Chavo, forming the tag team Los Guerreros. In contrast to a previous WCW storyline with his nephew, Chavo fully adopted his uncle's policy of "Lie, Cheat and Steal" to win matches. The duo entered the eight-team tournament for the new WWE Tag Team Championship and began a feud with the newly formed tag team of Kurt Angle and Chris Benoit. In one of the team's definitive moments, Chavo told Benoit that his former friend Guerrero was assaulted by his tag team partner Kurt Angle. Benoit ran to make the save, only to have himself locked inside a room. Guerrero then materialised in the room and assaulted Benoit with a steel chair.
Benoit and Angle managed to overcome their differences and eventually defeated Los Guerreros in the tournament semi-finals. Later on, Benoit and Angle won the WWE Tag Team Championships. Benoit and Angle then fought for a trophy for being the first WWE Tag Team Champion. Much to Benoit's surprise, Los Guerreros helped him win the match.
Los Guerreros would then be given another shot at the WWE Tag Team titles and the new champions, Edge and Rey Mysterio At Survivor Series 2002, Guerrero made Mysterio submit to The Lasso From El Paso. With this victory, Los Guerreros began their reign as the WWE Tag Team Champions, a reign that lasted until they were defeated by Team Angle. Los Guerreros participated at WrestleMania XIX as contenders for the Tag Titles, along with the team of Chris Benoit and Rhyno. Prior to Judgment Day, Chavo tore his bicep. This forced Guerrero to look for another partner. He chose Tajiri. They won the Tag Titles at Judgment Day in a ladder match. After Guerrero and Tajiri lost the titles to Team Angle on July 1, Guerrero turned on Tajiri, slamming his partner through the windshield of his low-rider truck.
Guerrero challenged Cena to a "Latino Heat" street fight for the United States Championship, which Guerrero won. Chavo made his return in this match, assisting Guerrero in executing his Frog Splash on Cena. On September 16, 2003, Los Guerreros defeated The World's Greatest Tag Team to regain the WWE Tag Team Championships. Eddie Guerrero thus held the United States Championship and one-half of the Tag Team Championships concurrently. Guerrero lost the United States Championship to The Big Show at No Mercy 2003 in October and then that same week Eddie and Chavo lost it to The Basham Brothers. As Los Guerreros attempted to regain the tag team titles, things began to go downhill between Chavo and Eddie, Chavo's father Chavo Classic tried to get both uncle and nephew on the same page but it was all a ruse and Chavo Classic joined his son. Eddie and Chavo fought one another at the 2004 Royal Rumble in a match that was won by Eddie.
The two remained separate for sometime until Eddie turned heel in 2005 with Chavo playing as a puppet master to create tension between Eddie and his tag team parter Rey Mysterio. The two however never teamed up again as Los Guerreros as first Chavo Guerrero got moved to RAW under the Kerwin White gimmick and then tragically Eddie died in November 2005.