Listed is every championship that Chris Jericho has won during his career. Thanks to Chris Jericho.com for the earlier title information and Wrestling-Titles.com and Wrestling Information Archive for some additional info.
Rocky Mountain Wrestling
CANADIAN HEAVYWEIGHT CHAMPIONSHIP
January 29, 1993 - Won from Biff Wellington - Calgary, AB, Canada
February 12, 1993 - Lost to Jason the Terrible - Calgary, AB, Canada
Empressa Mexicana Lucha Libre
WWA TAG TEAM CHAMPIONSHIP
July 21, 1993 - With Dandy, won from Texano & Silver King - Mexico City, Mexico
September 1, 1993 - Lost to Texano & Silver King - Mexico City, Mexico
Empressa Mexicana Lucha Libre
NWA MIDDLEWEIGHT CHAMPIONSHIP
December 4, 1993 - Won from Mano Negra - Mexico City, Mexico
November 8, 1994 - Lost to Ultimo Dragon - Tokyo, Japan
Rocky Mountain Wrestling
CANADIAN MID HEAVYWEIGHT CHAMPIONSHIP
January 7, 1994 - Won from Steve Rivers - Calgary, AB, Canada
February 4, 1994 - Lost to Lance Storm - Calgary, AB, Canada
Wrestling And Romance
INTERNATIONAL JUNIOR HEAVYWEIGHT CHAMPIONSHIP
June 4, 1995 - Won from Gedo - Tokyo, Japan
July 28, 1995 - Lost to Ultimo Dragon - Tokyo, Japan
Wrestle Association R
INTERNATIONAL JUNIOR TAG TEAM CHAMPIONSHIP
February 23, 1996 - With Gedo, won from Lance Storm & Yuji Yasuraoka - Sendai, Japan
March 27, 1996 - Lost to Lance Storm & Yuji Yasuraoka - Nagoya, Japan
Extreme Championship Wrestling
ECW TELEVISION CHAMPIONSHIP
June 22, 1996 - Won from Pitbull #2 - Philadelphia, PA
July 13, 1996 - Lost to Shane Douglas - Philadelphia, PA
World Championship Wrestling
WCW CRUISERWEIGHT CHAMPIONSHIP
June 28, 1997 - Won from Syxx - Los Angeles, CA
July 28, 1997 Lost to Alex Wright - Charleston, WV
#2 - August 12, 1997 - Won from Alex Wright - Colorado Springs, CO
September 14, 1997 - Lost to Eddy Guerrero - Winston-Salem, NC
#3 - January 24, 1998 - Won from Rey Mysterio Jr. - Dayton, OH
May 17, 1998 - Lost to Dean Malenko - Worcester, MA
#4 - June 15, 1998 - Awarded - Uniondale, NY [1]
July 12, 1998 - Lost to Rey Mysterio Jr. - San Diego, CA
#5 - July 13,1998 - Awarded - Las Vegas, NV [2]
August 8, 1998 - Lost to Juventud Guerrera - Sturgis, SD
World Championship Wrestling
WCW WORLD TELEVISION CHAMPIONSHIP
August 10, 1998 - Won from Stevie Ray - Rapid City, SD
November 30, 1998 - Lost to Konnan - Chattanooga, TN
World Championship Wrestling
WCW WORLD HEAVYWEIGHT CHAMPIONSHIP
October 21, 2001 - Won from The Rock - St. Louis, MO
November 5, 2001 - Lost to The Rock - Uniondale, NY
#2 - December 9, 2001 - Won from The Rock - San Diego, CA [6]
March 17, 2002 - Lost to Triple H - Toronto, ON, Canada
World Wrestling Entertainment
WWE INTERCONTINENTAL CHAMPIONSHIP
December 12, 1999 - Won from Chyna - Fort Lauderdale, FL
December 28, 1999 - Title vacated - Richmond, VA [3]
January 3, 2000 - Title is awarded to both Jericho and Chyna - Miami, FL [4]
#2 - January 23, 2000 - Won from Chyna - New York, NY [5]
February 27, 2000 - Lost to Kurt Angle - Hartford, CT
#3 - May 4, 2000 - Won from Chris Benoit - Richmond, VA
May 8, 2000 - Lost to Chris Benoit - Uniondale, NY
#4 - January 21, 2001 - Won from Chris Benoit - New Orleans, LA
April 5, 2001 - Lost to Triple H - Oklahoma City, OK
#5 - September 16, 2002 - Won from Rob Van Dam - Denver, CO
September 30, 2002 - Lost to Kane - Houston, TX
#6 - October 27, 2003 - Won from Rob Van Dam - Fayetteville, NC
October 27, 2003 - Lost to Rob Van Dam - Fayetteville, NC
#7 - September 13, 2004 - Won from Christian - Portland, OR [7]
October 19, 2003 - Lost to Shelton Benjamin - Milwaukee, WI
#8 - March 10, 2008 - Won from Jeff Hardy - Milwaukee, WI
June 29, 2008 - Lost to Kofi Kingston - Dallas, TX
World Wrestling Entertainment
WWE EUROPEAN CHAMPIONSHIP
April 2, 2000 - Won from Kurt Angle and Chris Benoit - Anahiem, CA
April 3, 2000 - Lost to Eddie Guerrero - Los Angeles, CA
World Wrestling Entertainment
WWE HARDCORE CHAMPIONSHIP
May 28, 2001 - Won from The Big Show - Calgary, AB, Canada
May 28, 2001 - Lost to Rhyno - Calgary, AB, Canada
World Wrestling Entertainment
WWE TAG TEAM CHAMPIONSHIP
May 21, 2001 - With Chris Benoit, won from "Stone Cold" Steve Austin & Triple H - San Jose, CA
June 21, 2001 - Lost to The Dudley Boyz - Orlando, FL
#2 - October 22, 2001 - With The Rock, won from The Dudley Boyz - Kansas City, MO
November 1, 2001 - Lost to Test & Booker T. - Cincinnati, OH
#3 - October 14, 2002 - With Christian, won from The Hurricane & Kane - Montreal, QC, Canada
December 15, 2002 - Lost to Booker T. & Goldust - Fort Lauderdale, FL
World Wrestling Entertainment
WWE CHAMPIONSHIP
December 9, 2001 - Won from "Stone Cold" Steve Austin - San Diego, CA [6]
March 17, 2002 - Lost to Triple H - Toronto, ON, Canada
World Wrestling Entertainment
WORLD HEAVYWEIGHT CHAMPIONSHIP
September 7, 2008 - Won from Batista, Kane, Rey Mysterio and John Bradshaw Layfield - Cleveland, OH [8]
October 26, 2008 - Lost to Batista - Phoenix, AZ
#2 - November 3, 2008 - Won from Batista - Tampa, FL
November 23, 2008 - Lost to John Cena - Boston, MA
[1] Dean Malenko vacates the title 06/11/98 and the title is awarded to the previous champion, Chris Jericho.
[2] Title is returned to Chris Jericho because of the interference by Dean Malenko, who is suspended, during the title match on previous day.
[3] Title is vacated after a match against Chyna ends in a double pin.
[4] Title is awarded to both Chris Jericho and Chyna as co-champions.
[5] Chris Jericho wins sole possession of the title by winning a triple threat match against Chyna and Hardcore Holly.
[6] Chris Jericho becomes undisputed world champion by unifying the WCW and WWF titles.
[7] Edge is stripped of title 09/06/04 due to injury. Chris Jericho defeats Christian to win the vacant title.
[8] Champion CM Punk is unable to compete and Chris Jericho is named his replacement. Jericho wins the match and the title.