Mexican National Trios Championship (1 time) – with Octagón and Super Muñeco
Mexican National Welterweight Championship (1 time)
AAA Hall of Fame: Class of 2007

WCW Cruiserweight Championship (5 times)
WCW Cruiserweight Tag Team Championship (1 time) – with Billy Kidman
WCW World Tag Team Championship (3 times) – with Billy Kidman (1), Konnan (1), and Juventud Guerrera (1)

WWE
Royal Rumble (Royal Rumble 2006)
Triple Crown Champion
World Heavyweight Championship (1 time)
WWE Intercontinental Championship (2 times)
WWE Tag Team Championship (4 times) – with Edge (1), Rob Van Dam (1), Eddie Guerrero (1), and Batista (1)
WWE Cruiserweight Championship (6 times)

Wrestling Observer Newsletter awards
Best Flying Wrestler (1995–1997, 2002–2004)
Best Wrestling Maneuver (1995) West Coast Pop
Match of the Year (2002) with Edge versus Chris Benoit and Kurt Angle, WWE No Mercy, October 20
Most Outstanding Wrestler (1996)
Rookie of the Year (1992)

Mysterio has a wide variety of tattoos, including dedications to his family.
Mysterio and his wife Angie have two children, a son, Dominik, born 1997, and a daughter, Aaliyah, born 2001. In an interview with The Miami Herald in January 2009, Mysterio revealed that he and his wife are expecting their third child. He has tattoos of his two children's names on his right and left biceps. He also has tattoos dedicated to his wife, Angie.His wife and two oldest children have all appeared on wrestling shows alongside Gutiérrez, including Dominik being in a storyline between Rey and Eddie Guerrero.

On March 19, 2007, Sports Illustrated posted on its website an article in its continuing series investigating a steroid and HGH ring used by a number of professional athletes in several sports. That article mentioned several current and former WWE wrestlers, including Mysterio who was alleged to have obtained nandrolone and stanozolol. WWE subsequently stated that the allegations preceded the Talent Wellness program WWE launched in February 2006. On August 27, 2009, WWE announced that Gutiérrez would receive a 30 day suspension due to a violation of the wellness program. Days later Gutiérrez defended himself in a newspaper interview by explaining the drugs as being on a prescription for his knee and arm. While the Wellness Policy allows for prescribed drugs, Mysterio further contested he had been on a family holiday and subsequently in Europe promoting SummerSlam, giving him only a day to provide the prescription after being notified.

He has a cousin who wrestles in the Tijuana area as El Hijo de Rey Misterio ("The Son of Rey Misterio"). He wears a similar mask and ring attire. Gutiérrez' father's name is Roberto Sr., and his mother's name is Maria and he has three brothers: Luis, Lalo, and Roberto Gutiérrez. Ocscar Gutiérrez is friends with Noah "Wuv" Bernardo, of P.O.D.. The two met while in high school and P.O.D. performs Mysterio's theme song, Booyaka 619. He is a Roman Catholic, frequently crossing himself before every match and bearing numerous religious tattoos on his body, most notably a cross on his chest attached to rosaries as well as other crosses and allusions to God

Oscar Gutierrez was born on December 11, 1974. He was trained by his uncle Rey Misterio Sr. and made his pro debut in 1989. He began a feud with Psicosis using the ring name Colibrí (Spanish for hummingbird). The feud lasted several years, continuing even after Mysterio's career moved to the United States of America.

In Asistencia Asesoría y Administración (AAA) he feuded with Juventud Guerrera, including a tag match with Misterio, Sr. and Misterio, Jr. taking on Juventud and his father Fuerza Guerrera.

After AAA, Rey Mysterio Jr. along with Juventud Guerrera and Psicosis were contacted by Paul Heyman to sign a contract for ECW in the states. Though Rey Mysterio Jr. only had a brief stint in ECW, he had a Mexican Death match with Psicosis that was ranked best match of the year 1995. Mysterio left ECW however to join World Championship Wrestling.