Barry Bonds, San Francisco, 2001, with 73 Home Runs. [ Source: http://baseball-almanac.com/hitting/hihr4.shtml ]

Here's a list of all the players that hit at least 50 home runs in a single season as of April 2006: --------------------- YEAR HR 1 Barry Bonds 2001 73 2 Mark McGwire 1998 70 3 Sammy Sosa 1998 66 4 Mark McGwire 1999 65 5 Sammy Sosa 2001 64 6 Sammy Sosa 1999 63 7 Roger Maris 1961 61 8 Babe Ruth 1927 60 9 Babe Ruth 1921 59 T10 Mark McGwire 1997 58 T10 Hank Greenberg 1938 58 T10 Jimmie Foxx 1932 58 T13 Alex Rodriguez 2002 57 T13 Luis Gonzalez 2001 57 T15 Hack Wilson 1930 56 T15 Ken Griffey Jr. 1997 56 T15 Ken Griffey Jr. 1998 56 T18 Mickey Mantle 1961 54 T18 Ralph Kiner 1949 54 T18 Babe Ruth 1920 54 T18 Babe Ruth 1928 54 T22 Mark McGwire 1996 52 T22 Willie Mays 1965 52 T22 Mickey Mantle 1956 52 T22 Alex Rodriguez 2001 52 T22 Jim Thome 2002 52 T22 George Foster 1977 52 T28 Ralph Kiner 1947 51 T28 Willie Mays 1955 51 T28 Johnny Mize 1947 51 T28 Andruw Jones 2005 51 T28 Cecil Fielder 1990 51 T33 Sammy Sosa 2000 50 T33 Greg Vaughn 1998 50 T33 Albert Belle 1995 50 T33 Brady Anderson 1996 50 T33 Jimmie Foxx 1938 50

Gotta Cite Sources: www.factmonster.com/ipka/A0113265.html HR- Player/Team- Year 73 Barry Bonds, San Francisco (N.L)2001 70 Mark McGwire, St. Louis (N.L.) 1998 66 Sammy Sosa, Chicago (N.L.) 1998 65 Mark McGwire, St. Louis (N.L.) 1999 64 Sammy Sosa, Chicago (N.L.) 2001 63 Sammy Sosa, Chicago (N.L.) 1999 61 Roger Maris, New York (A.L.) 1961 60 Babe Ruth, New York (A.L.) 1927 59 Babe Ruth, New York (A.L.) 1921 58 Jimmie Foxx, Philadelphia (A.L.)1932 58 Hank Greenberg, Detroit (A.L.) 1938 58 Mark McGwire, Oakland (A.L.), 1997 58 Ryan Howard, Philadelphia (N.L.)2006 57 Luis Gonzalez. Arizona (N.L.) 2001 57 Alex Rodriguez, Texas (A.L.) 2002 56 Hack Wilson, Chicago (N.L.) 1930 56 Ken Griffey, Jr., Seattle (A.L.)1997 56 Ken Griffey, Jr., Seattle (A.L.)1998 54 Babe Ruth, New York (A.L.) 1920 54 Babe Ruth, New York (A.L.) 1928 54 Ralph Kiner, Pittsburgh (N.L.) 1949 54 Mickey Mantle, New York (A.L.) 1961 54 David Ortiz, Boston (A.L.) 2006 52 Mickey Mantle, New York (A.L.) 1956 52 Willie Mays, San Francisco (N.L.) 1965 52 George Foster, Cincinnati (N.L.) 1977 52 Mark McGwire, Oakland (A.L.) 1996 52 Alex Rodriguez, Texas (A.L.) 2001 52 Jim Thome, Cleveland (A.L.) 2002 51 Ralph Kiner, Pittsburgh (N.L.) 1947 51 John Mize, New York (N.L.) 1947 51 Willie Mays, New York (N.L.) 1955 51 Cecil Fielder (A.L.) 1990 51 Andruw Jones, Atlanta (N.L.) 2005 50 Jimmie Foxx, Boston (A.L.) 1938 50 Albert Belle, Cleveland (A.L.) 1995 50 Brady Anderson, Baltimore (A.L.)1996 50 Sammy Sosa, Chicago (N.L.) 2000 50 Greg Vaughn, San Diego (N.L.) 1998 49 Babe Ruth, New York (A.L.) 1930 49 Lou Gehrig, New York (A.L.) 1934 49 Lou Gehrig, New York (A.L.) 1936 49 Ted Kluszewski, Cincinnati (N.L.) 1954 49 Willie Mays, San Francisco (N.L.) 1962 49 Harmon Killebrew, Minnesota (A.L.) 1964 49 Frank Robinson, Baltimore (A.L.) 1966 49 Harmon Killebrew, Minnesota (A.L.) 1969 49 Mark McGwire, Oakland (A.L.) 1987 49 Andre Dawson, Chicago (N.L.) 1987 49 Ken Griffey, Jr., Seattle (A.L.)1996 49 Larry Walker, Colorado (N.L.) 1997 49 Albert Belle, Chicago (A.L.) 1998 49 Barry Bonds, San Francisco (N.L.)2000 49 Shawn Green, Los Angeles (N.L.) 2001 49 Todd Helton, Colorado (N.L.) 2001 49 Jim Thome, Cleveland (A.L.) 2001 49 Sammy Sosa, Chicago (N.L.) 2002 49 Albert Pujols, St. Louis (N.L.) 2006 48 Jimmie Foxx, Philadelphia (A.L.) 1933 48 Harmon Killebrew, Minnesota (A.L.) 1962 48 Frank Howard, Washington (A.L.) 1969 48 Willie Stargell, Pittsburgh (N.L.) 1971 48 Dave Kingman, Chicago (N.L.) 1979 48 Mike Schmidt, Philadelphia (N.L.) 1980 48 Albert Belle, Cleveland (A.L.) 1996 48 Ken Griffey, Jr., Seattle (A.L.)1999 48 Adrian Beltre, Los Angeles (N.L.)2004 48 Alex Rodriguez, New York (A.L.) 2005 47 Babe Ruth, New York (A.L.) 1926 47 Ralph Kiner, Pittsburgh (N.L.) 1950 47 Ed Mathews, Milwaukee (N.L.) 1953 47 Ernie Banks, Chicago (N.L.) 1958 47 Willie Mays, San Francisco (N.L.) 1964 47 Hank Aaron, Atlanta (N.L.) 1971 47 Reggie Jackson, Oakland (A.L.) 1969 47 George Bell, Toronto (A.L.) 1987 47 Kevin Mitchell, San Francisco (N.L.) 1989 47 Andres Galarraga, Colorado (N.L.)1996 47 Juan Gonzalez, Texas (A.L.) 1996 47 Rafael Palmeiro, Texas (A.L.) 1999 47 Jeff Bagwell, Houston (N.L.) 2000 47 Troy Glaus, Anaheim (A.L.) 2000 47 Rafael Palmeiro, Texas (A.L.) 2001 47 Alex Rodriguez, Texas (A.L.) 2003 47 Jim Thome, Philadelphia (N.L.) 2003 47 Albert Pujols, St. Louis (N.L.) 2004 47 David Ortiz, Boston (A.L.) 2005 46 Babe Ruth, New York (A.L.) 1924 46 Babe Ruth, New York, (A.L.) 1929 46 Babe Ruth, New York (A.L.) 1931 46 Lou Gehrig, New York (A.L.) 1931 46 Joe DiMaggio, New York (A.L.) 1937 46 Ed Mathews, Milwaukee (N.L.) 1959 46 Orlando Cepeda, San Francisco (N.L.) 1961 46 Jim Rice, Boston (A.L.) 1978 46 Juan Gonzalez, Texas (A.L.) 1993 46 Barry Bonds, San Francisco (N.L.) 1993 46 Jose Canseco, Toronto (A.L.) 1998 46 Vinnie Castilla, Colorado (N.L.)1998 46 Barry Bonds, San Francisco (N.L.)2002 46 Adam Dunn, Cincinnati (N.L.) 2004 46 Derrek Lee, Chicago (N.L.) 2005 46 Alfonso Soriano, Washington (N.L.)2006 45 Ernie Banks, Chicago (N.L.) 1959 45 Harmon Killebrew, Minnesota (A.L.) 1963 45 Willie McCovey, San Francisco (N.L.) 1969 45 Johnny Bench, Cincinnati (N.L.) 1970 45 Gorman Thomas, Milwaukee (A.L.) 1979 45 Hank Aaron, Milwaukee (N.L.) 1962 45 Ken Griffey, Jr., Seattle (A.L.) 1993 45 Juan Gonzalez, Texas (A.L.) 1998 45 Manny Ramirez, Cleveland (A.L.) 1998 45 Chipper Jones, Atlanta (N.L.) 1999 45 Greg Vaughn, Cincinnati (N.L.) 1999 45 Barry Bonds, San Francisco (N.L.)2003 45 Richie Sexson, Milwaukee (N.L.) 2003 45 Barry Bonds, San Francisco (N.L.)2004 45 Manny Ramirez, Boston (A.L.) 2005 45 Lance Berkman, Houston (N.L.) 2006