The following are the baseball events of the year 1904 throughout the world.
American League: Boston Americans
National League: New York Giants
World Series: New York (NL) declined challenge by Boston (AL)
May 5 – Cy Young pitches a perfect game, as the Boston Americans defeat the Philadelphia Athletics, 3–0. This is considered the first perfect game in the modern era.
June 11 – Chicago Cubs pitcher Bob Wicker pitches nine innings without allowing a hit. He surrenders a hit in the 10th inning, but it would be the only hit he allows in the game. The Cubs would go on the beat the New York Giants, 1–0, in 12 innings.
June 20 - Duff Cooley of the Boston Beaneaters hits for the cycle in the second game of a doubleheader against the Philadelphia Phillies in a 9-0 Boston victory.
June 23 – Kip Selbach of the Washington Senators ties a record by committing 3 errors from the outfield in one inning.
August 17 – Boston Americans pitcher Jesse Tannehill tosses a no-hitter against the Chicago White Sox in a 6–0 Boston win.
October 4 – New York Giants outfielder Sam Mertes hits for the cycle in a 7-3 loss to the St. Louis Cardinals.
The World Series was cancelled when New York Giants owner, John T. Brush, refused to play Boston. Highlanders P Jack Chesbro throws a pennant-losing wild pitch at home against Boston.
January 1 – Ethan Allen
January 3 – Bill Cissell
January 7 – Clay Roe
January 10 - Lou Dials
January 13 – Bunny Hearn
January 16 – Jo-Jo Morrissey
January 18 – Len Koenecke
January 19 – Jimmy Boyle
January 20 – Denny Sothern
January 22 – John Milligan
January 24 – Neal Finn
January 26 – George Blaeholder
January 28 – Dutch Hoffman
January 29 – Ray Hayworth
February 7 – Andy Reese
February 9 – Roy Mahaffey
February 10 – Hal Anderson
February 13 – Cecil Bolton
February 13 – Charlie Fitzberger
February 15 – Oscar Estrada
February 27 – Chick Fullis
February 27 – Bud Teachout
February 29 – Pepper Martin
March 5 – Lou Rosenberg
March 16 – Buddy Myer
March 21 – Frank Sigafoos
March 21 – Red Rollings
March 22 – Bob Elson
March 30 – Ripper Collins
March 31 – Sam Dailey
March 31 – Red Rollings
April 1 – Jack Cummings
April 9 – Guy Cantrell
April 9 – Fred Frankhouse
April 11 – Dutch Ussat
April 30 – Neal Baker
April 30 – Tony Murray
May 9 – Paul Hinson
May 9 – Brad Springer
May 16 – Abe White
May 18 – Red Smith
May 20 – Pete Appleton
May 22 – Ed Morgan
May 25 – Buz Phillips
May 26 – Frank Ragland
May 26 – Bill Shores
June 4 – Lefty Atkinson
June 13 – John O'Connell
June 15 – Ed Pipgras
June 15 – Pid Purdy
June 15 – Hank Winston
June 7 – Dusty Boggess
June 12 – Bill Foster
June 24 – Bobby Reeves
July 2 – Pete Susko
July 3 – Luke Hamlin
July 4 – Ed Cotter
July 24 – Mel Ingram
July 5 – Bump Hadley
July 9 – Art Daney
July 14 – Max West
July 15 – Ray Wolf
July 18 – Marty Karow
July 19 – Mark Koenig
August 5 – Vic Frazier
August 6 – Herb Cobb
August 14 – Les Cox
August 17 – Augie Walsh
September 4 – Bud Morse
September 6 – Willie Underhill
September 10 – Arlie Tarbert
September 16 – Edgar Barnhart
September 25 – Paul Hopkins
September 26 – Jess Cortazzo
September 30 – Johnny Allen
October 2 – Tom Angley
October 5 – Sam West
October 7 – Chuck Klein
October 9 – Gordon Slade
October 13 – Howie Carter
October 15 – Bill Lewis
October 16 – Boom-Boom Beck
October 24 – Harry Smythe
October 25 – Andy Cohen
October 26 – Monk Sherlock
October 27 – Frank Bennett
October 28 – Liz Funk
October 28 – Joe O'Rourke
October 31 – Allyn Stout
November 1 – Johnny Burnett
November 4 – Earl Mattingly
November 5 – Ollie Sax
November 15 – George Cox
November 16 – Mike Smith
November 19 – Elmer Tutwiler
November 24 – Billy Rogell
December 5 – Ray Fitzgerald
December 12 – Ray Boggs
December 13 – Bill Windle
December 16 – Joe Berry
December 20 – Spud Davis
December 23 – Howie Williamson
December 25 – Bill Akers
December 25 – Lloyd Brown
December 25 – Bill Sweeney
December 27 – John Shea
January 1 – George Radbourn, 47, pitcher who played briefly for the 1883 Detroit Wolverines.
January 31 – Dan Mahoney, 39, catcher and first baseman for the 1892 Cincinnati Reds and 1894 Washington Senators.
March 22 – Art McCoy, 39, second baseman who played in two games with the 1889 Washington Nationals.
March 25 – Harry Arundel, 49, pitcher who played with the Brooklyn Atlantics (1875), Pittsburgh Alleghenys (1892) and Providence Grays (1884).
March 28 – George Seward, 53 [?], outfielder who played in part of three seasons for the St. Louis Brown Stockings (1875, 1882) and New York Mutuals (1876).
April 11 – Shorty Fuller, 36, shortstop for the Washington Nationals, St. Louis Brown Stockings and New York Giants from 1888 to 1896, who scored more than 100 runs in the 1890 and 1891 seasons.
April 18 – Charlie Ziegler, 29, infielder for the 1889 Cleveland Spiders and 1900 Philadelphia Phillies.
April 20 – John Galvin, 61, second baseman for the 1872 Brooklyn Atlantics.
April 20 – Gus McGinnis, 33, pitcher and outfielder who played with the Chicago Colts and Philadelphia Phillies in 1he 1893 season.
April 27 – Bobby Cargo, 33, shortstop for the 1892 Pittsburg Pirates.
May 4 – Frank Quinlan, 35, catcher and outfielder who appeared in two games for the 1891 Boston Reds.
May 25 – John Hayes, 49, outfielder who hit .143 in five games for the 1876 New York Mutuals.
June 3 – Bill Pfann, 41 [?], pitcher for the 1884 Cincinnati Reds.
June 6 – Chippy McGarr, 41, third baseman who hit .269 in 827 games for several teams over the course of 10 seasons from 1884 to 1896.
June 19 – Marshall Quinton, 52, catcher who played from 1884 to 1885 for the Richmond Virginians and Philadelphia Athletics teams of the American Association.
July 24 – Ernie Mason, 34 [?], pitcher and outfielder for the 1894 St. Louis Browns of the National League.
August 22 – Charlie Dewald, 36, pitcher for the 1890 Cleveland Infants.
September 20 – Jack Neagle, 46, pitcher for the Cincinnati Reds, Philadelphia Quakers, Baltimore Orioles and Pittsburg Alleghenys from 1879 to 1884.
October 16 – Mike Slattery, 37, center fielder who hit .251 in five seasons and was a member of the New York Giants World Champion teams of 1888 and 1889.
October 28 – Sam Field, 56, catcher who hit .146 for three different teams between 1875 and 1876.
November 2 – Henry Austin, 60, outfielder and a .243 batter in 23 games for the 1873 Elizabeth Resolutes.
November 4 – Charlie Reilley, 47 [?], catcher who hit .210 from 1879 through 1884 for the Troy Trojans, Cincinnati Reds, Detroit Wolverines, Worcester Ruby Legs and Boston Reds.
November 4 – Jim Shanley, 50, outfielder who played two games for the 1876 New York Mutuals.
November 7 – Fred Carroll, 40, catcher and outfielder from 1884 to 1891, who hit a career .284 average in 754 games with the Columbus Buckeyes and for the Pittsburgh teams Alleghenys, Burghers and Pirates.
November 20 – Dell Darling, 42, catcher and a career .240 hitter for three teams of three different leagues from 1887 to 1891.
December 13 – Bob Murphy, 37, pitcher who posted a 4–9 record for the New York Giants and Brooklyn Gladiators during the 1890 season.
December 18 – John Clapp, 53, catcher and manager for several teams from 1872 through 1883, who hit a career .283 average in 588 games, including three .300 seasons.