Striking out 20 batters in a single game is one of the rarest feats in all of baseball, rarer, in fact, than a perfect game. It has happened in a nine-inning game only a handful of times in over a century of major-league play, and the names attached to it read like a pitching hall of fame: Roger Clemens, Kerry Wood, Max Scherzer. To dominate an entire lineup so thoroughly that nearly three-quarters of the outs come on strikes is the ultimate display of pitching power.
But “most strikeouts in one game” actually has two answers, and the distinction matters. The record for a standard nine-inning game is 20, while the record for a game of any length is 21, set by a little-known pitcher in a 16-inning marathon. Understanding both, and the near-misses that came agonizingly close, is the key to appreciating this remarkable corner of baseball history.
The chart below is a complete breakdown: the 20-strikeout club, the all-time any-length record, the pitchers who came up just short, the team records, and the key facts. Take a look, then we’ll get into the details.
Contents
The two records, and why they differ
When people ask about the most strikeouts in a single game, the answer depends on how you define “game.” For a standard nine-inning game, the record is 20 strikeouts. But baseball games can run longer, and in a game of any length, the record is 21, set by Tom Cheney in a 16-inning marathon in 1962. Because that extra inning of opportunity makes a direct comparison unfair, the baseball world treats the nine-inning mark as the more meaningful and frequently cited record.
This distinction is the key to understanding the whole topic. The nine-inning record is about pure, concentrated dominance over a regulation game, every pitcher gets the same 27 outs to work with. Cheney’s 21, by contrast, came over nearly twice as many innings. Both are remarkable, but they measure slightly different things, which is why you will often see them listed separately.
The 20-strikeout club
The nine-inning record of 20 has been reached four times by three pitchers, an exclusive fraternity. Roger Clemens started it all on April 29, 1986, when the 23-year-old “Rocket” fanned 20 Mariners, becoming the first pitcher in history to reach the mark. Remarkably, Clemens did it again a decade later, on September 18, 1996, against the Tigers, making him the only pitcher ever to record two 20-strikeout games.
In between and after came two more legends. On May 6, 1998, a 20-year-old rookie named Kerry Wood announced himself to the world by striking out 20 Astros at Wrigley Field, tying the record in just his fifth career start. Then on May 11, 2016, Max Scherzer matched the mark against his former team, the Tigers, and did so with the fewest pitches of any of the four, needing only 119. One stunning detail unites all of these games: not one of these pitchers walked a single batter.
The all-time record nobody remembers
While Clemens, Wood, and Scherzer are household names, the man who holds the record for most strikeouts in a game of any length is not. Tom Cheney, a journeyman right-hander for the Washington Senators, struck out 21 Baltimore Orioles on September 12, 1962, in an epic 16-inning complete game. It remains the single-game strikeout record by any measure, and it has stood for more than six decades.
Cheney’s feat is one of baseball’s great forgotten achievements. Pitching all 16 innings, an unthinkable workload by modern standards, he simply outlasted and overpowered the Orioles inning after inning. The performance is a relic of a bygone era when complete games were common and pitch counts were an afterthought, and it is unlikely ever to be broken in today’s game of strict pitch limits and bullpen specialization.
The Randy Johnson asterisk
No discussion of this record is complete without the curious case of Randy Johnson. On May 8, 2001, the Big Unit struck out 20 Cincinnati Reds, the same total as the nine-inning record holders. But there is a catch: the game was tied after nine innings and went to extras, and Johnson was relieved after his ninth inning. Because the game itself extended beyond nine innings, his performance occupies a strange middle ground.
For this reason, you will sometimes see it said that “five times” a pitcher has struck out 20 in nine innings or fewer, counting Johnson, and other times that only four official nine-inning performances exist, excluding him. Both framings are defensible; it simply depends on whether you focus on Johnson’s nine innings of work or on the length of the game he pitched in. Like the others, Johnson did not walk a batter that night.
The pitchers who came up just short
For every pitcher who reached 20, several came agonizingly close with 19 in a nine-inning game. The list includes Steve Carlton, who fanned 19 Mets in 1969 but lost the game when Ron Swoboda hit two two-run homers, and Tom Seaver, whose 1970 gem against the Padres ended with him striking out the final 10 batters he faced, a consecutive-strikeout record that still stands today. David Cone, Nolan Ryan, and Randy Johnson (twice in 1997) also reached 19.
One rung below, 20 different pitchers have struck out at least 18 in a nine-inning game, a threshold widely considered the mark of a truly dominant outing. Bob Feller was the first to do it in the modern era, back in 1938. Tellingly, only Clemens and Johnson have ever struck out 18 or more in a nine-inning game on three separate occasions, underscoring how these two power pitchers stood apart even among the game’s hardest throwers.
When a whole staff piles them up
Individual records aside, teams can rack up even gaudier strikeout totals over the course of a long extra-inning game using multiple pitchers. The record for one team’s pitching staff is 26 strikeouts, achieved in several marathon extra-inning contests. And in a single game on May 7, 2017, the Cubs and Yankees combined for 48 strikeouts across 18 innings, the most ever by both teams in one game.
These totals are a different kind of achievement, products of length and bullpen depth rather than one pitcher’s single-game brilliance. They belong in any complete discussion of game strikeout records, but they should not be confused with the headline feat: one starting pitcher mowing down 20 hitters in a regulation nine-inning game.
Final Word
The most strikeouts in a single nine-inning game is 20, a feat reached just four times by three pitchers, Roger Clemens (twice), Kerry Wood, and Max Scherzer, with Randy Johnson’s 20-in-an-extra-inning-game earning its own asterisk. Stretch the definition to a game of any length, and the record belongs to Tom Cheney, whose 21 strikeouts over 16 innings in 1962 has never been topped. Rarer than a perfect game, the 20-strikeout performance remains one of pitching’s ultimate achievements.
What unites all these legendary outings is a level of dominance most pitchers can only dream of, and a shared, almost eerie detail: in every 20-strikeout game, the pitcher walked no one. For more on baseball’s rarest pitching feats, see our explainer on the difference between a no-hitter and a perfect game.