• July 12: Most inside-the-park home runs in a game – 3 by Tom McCreery^[1]

• Most home runs, season – 29 by Babe Ruth.

• July 19: Most home runs, season – 30 by Babe Ruth; ended the season with 54.
• Highest slugging percentage, season – .847 by Ruth.

• July 18: Most career home runs – 139 by Babe Ruth; ended his career in 1935 with 714.
  • Ruth's passing of Roger Connor for the career home-run record was not recognized at the time. Connor's career total of 138 was not accurately documented until the 1970s; at one time, he was thought to have hit only 131.
• September 15: Most home runs, season – 55 by Ruth; ended the season with 59.

• September 27: Most RBI, season – 172 by Lou Gehrig; ended season with 175.
• September 30: Most home runs, season – 60 by Babe Ruth.

• September 17: Most RBI, season – 176 by Hack Wilson; ended season with 191.

• July 10: Most hits in a game by a batter – 9 by Johnny Burnett^[2]

• July 2: Longest hitting streak in a single season – 45 by Joe DiMaggio; extended to 56.
• July 5: Longest hitting streak spanning one or more seasons – 46 by Joe DiMaggio; extended to 56.

• October 1: Most home runs, season – 61 by Roger Maris^[3]

• April 8: Most career home runs – 715 by Hank Aaron; ended his career in 1976 with 755.

• September 8: Most career hits – 4,190 by Pete Rose; ended his career in 1986 with 4,256.

• August 14: Most home runs by a rookie, season – 39 by Mark McGwire; later extended to 49.

• May 1: Most career stolen bases – 939 by Rickey Henderson; ended his career in 2003 with 1,406.

• September 6: Most consecutive games played – 2,131 by Cal Ripken Jr.; later extended to 2,632 in 1998.

• September 4

9: Most teams with which a player has hit 20 home runs in a season – 2 by Mark McGwire

• June 25: Most home runs in a calendar month – 19 by Sammy Sosa (extended to 20 on June 30).
• September 8: Most home runs, season – 62 by Mark McGwire; later extended to 70. Sosa also broke the 37-year-old record held by Roger Maris and was briefly the sole record-holder, hitting his 66th home run of the season (which would be his final total) before McGwire did.

• April 23: Most grand slams hit in one inning – 2 by Fernando Tatís^[4]
• Most grand slams surrendered in one inning – 2 by Chan Ho Park^[5]

• October 4: Most career runs – 2,246 by Rickey Henderson; ended his career in 2003 with 2,295
• October 5: Most home runs, season – 71 by Barry Bonds (hit #72 in same game; finished season with 73)
• Highest slugging percentage, season – .863 by Bonds.

• April 30: Most franchises against which a pitcher has earned a win: 30 by Al Leiter
• Highest on-base percentage, season – .582 by Barry Bonds.

• September 17: Most extra-base hits, season, by a team – 608 by Boston Red Sox

• July 10: Most intentional walks, season – 68 by Barry Bonds; broke his own record; finished season with 120
• October 6: Most hits in one season – 262 by Ichiro Suzuki
• Highest on-base percentage, season – .609 by Bonds.

• June 8: Youngest player to reach 400 home run mark – Alex Rodriguez, age 29 years, 316 days

• April 28: Most consecutive games with a home run by a right-handed hitter – 7 by Kevin Mench
• April 29: Most home runs in the month of April – 14 by Albert Pujols

• August 4: Youngest player to reach 500 career home runs – Alex Rodriguez, age 32 years, 8 days
• August 7: Most home runs, career – 756 by Barry Bonds; later extended to 762

• April 2: Most consecutive games without an error for a first baseman – 194 by Kevin Youkilis; later extended to 238 games^[6]
• May 9: Most baserunners picked off, career – 92 Kenny Rogers (since stat was first recorded in 1974)
• May 16: Most consecutive starts with a no-decision – 9 by Shawn Chacón

• June 17: Most games caught – 2,227 by Iván Rodríguez; later extended to 2,427 games.

• August 4: Youngest player to reach 600 career home runs – Alex Rodriguez, age 35 years, 8 days^[7]

• August 2: Most games hitting home runs from both sides of the plate in a career – 12 by Mark Teixeira
• September 19: Most career saves – 602 by Mariano Rivera;^[8] later extended to 652 saves.

• April 17: Oldest pitcher to win a game – Jamie Moyer, age 49 years, 151 days.^[9] Extended record on May 16 (see below).
• May 16: Oldest player to drive in a run – Moyer, age 49 years, 180 days^[10]
• June 23: Most walk-off home runs – 13 by Jim Thome (since 1900)^[11]

• September 20: Most career grand slams – 24 by Alex Rodriguez; later extended to 25.

• October 21: Most consecutive postseason games with a home run – 6 by Daniel Murphy

• September 25: Most home runs by a rookie, season – 50 by Aaron Judge; later extended to 52.

• September 28: Most home runs by a rookie, season – 53 by Pete Alonso