Tim Keefe posted a 0.86 ERA in 1880. Nobody's touched it since.
But Keefe only pitched 105 innings that year, threw from 50 feet instead of 60, and batters weren't allowed to call for high or low pitches. The game was different.
Single-season ERA records tell stories about when they happened as much as who threw them. A 1.12 ERA in 1968—when the league average was 2.98—means something different than a 1.74 ERA in 2000, when the league average was 4.91.
Let's look at the lowest ERAs ever recorded and why some of them are more impressive than the raw numbers suggest.
All-Time Lowest Single-Season ERAs (Minimum 100 IP)
| Rank | Pitcher | Year | ERA | IP | Team |
|---|---|---|---|---|---|
| 1 | Tim Keefe | 1880 | 0.86 | 105 | Troy Trojans (NL) |
| 2 | Dutch Leonard | 1914 | 0.96 | 224.2 | Boston Red Sox (AL) |
| 3 | Mordecai Brown | 1906 | 1.04 | 277.1 | Chicago Cubs (NL) |
| 4 | Bob Gibson | 1968 | 1.12 | 304.2 | St. Louis Cardinals (NL) |
| 5 | Christy Mathewson | 1909 | 1.14 | 275.1 | New York Giants (NL) |
Only two pitchers have ever finished a season with an ERA under 1.00: Keefe and Leonard. Gibson's 1.12 is the lowest in the live-ball era (1920-present) by a wide margin.
1. Tim Keefe — 0.86 ERA (1880)
The Record Holder
Season: 1880 Troy Trojans
Record: 6-6
ERA: 0.86
Innings: 105.0
Complete Games: 12 (out of 12 starts)
Keefe's 0.86 ERA is the lowest in baseball history with enough innings to qualify. But the 1880 game was barely recognizable compared to modern baseball.
The pitching distance was 45 feet. Batters could call for high or low pitches. Foul balls didn't count as strikes. Despite going 6-6, Keefe's Troy Trojans finished 41-42.
Still, nobody's matched it. Keefe made the Hall of Fame in 1964.
2. Dutch Leonard — 0.96 ERA (1914)
The AL Record
Season: 1914 Boston Red Sox
Record: 19-5
ERA: 0.96
Innings: 224.2
Strikeouts: 176 (7.05 K/9)
Leonard's 0.96 ERA is the American League record and will probably never be beaten. He pitched during the dead-ball era when runs were scarce across baseball, but his ERA still beat the AL average by more than 2 runs.
Playing for the Red Sox alongside a rookie named Babe Ruth, Leonard went 19-5 but finished second to the Philadelphia Athletics in the standings. He was second in MLB with 7.05 strikeouts per nine innings.
Fun fact: There were two pitchers named Dutch Leonard. This one pitched 1913-1925. The other pitched 1933-1953 and was better (191 wins, 4 All-Star teams). Both were lefties.
3. Bob Gibson — 1.12 ERA (1968)
Here's where it gets interesting. Gibson's 1.12 ERA is the fourth-lowest all-time, but many consider it the most dominant pitching season ever.
The Year of the Pitcher
Season: 1968 St. Louis Cardinals
Record: 22-9
ERA: 1.12
Innings: 304.2
Complete Games: 28 (out of 34 starts)
Shutouts: 13
Strikeouts: 268
What makes this season legendary:
- Gibson never got pulled for another pitcher all season (only left for pinch hitters)
- Pitched 47 consecutive scoreless innings at one point
- Won 12 straight complete games in June and July (8 were shutouts)
- Allowed only 6 earned runs in 108 innings during that stretch (0.50 ERA)
- Set a World Series record with 17 strikeouts in Game 1
- Won NL MVP (rare for a pitcher)
The catch: 1968 was called "The Year of the Pitcher." The NL average ERA was 2.99. Seven NL pitchers finished under 2.20 ERA.
MLB changed the rules after this season, lowering the mound from 15 inches to 10 inches. These became known as the "Gibson Rules."
Why 1968 Was Different
Pitchers dominated in 1968 for several reasons:
- 15-inch mound gave pitchers a huge angle advantage
- Strike zone went from shoulders to knees (expanded in 1963)
- No designated hitter (came in 1973)
- Expansion had diluted hitting talent
League-wide MLB ERA was 2.98. By 1969 (after mound lowered), it jumped to 3.60.
The Modern Era: Pedro Martinez — 1.74 ERA (2000)
Pedro's 2000 season might be the most impressive pitching performance ever when you account for context.
The Steroid Era Masterpiece
Season: 2000 Boston Red Sox
Record: 18-6
ERA: 1.74
Innings: 217.0
Strikeouts: 284 (11.78 K/9)
Walks: 32
WHIP: 0.737 (lowest in modern history)
The context that matters:
- AL average ERA in 2000: 4.91
- Pedro's ERA was 3.17 runs better than league average
- Only 5 AL pitchers had ERAs under 4.00 all season
- This was the peak of the steroid era
- He pitched in Fenway Park (hitter-friendly)
- Faced DH every game
Roger Clemens finished second in AL ERA at 3.70—nearly double Pedro's 1.74.
Pedro struck out 284 batters and walked only 32. His 0.737 WHIP is the lowest qualifying mark in baseball history. He had more than twice as many strikeouts (284) as hits allowed (128).
Gibson vs Pedro: The Great Debate
Which season was better? Baseball nerds have argued this for 20+ years.
Gibson's advantages:
- Lower raw ERA (1.12 vs 1.74)
- More innings (304.2 vs 217.0)
- 28 complete games vs 7
- 13 shutouts vs 4
Pedro's advantages:
- Bigger gap vs league average (3.17 runs vs 1.78 runs)
- Better strikeout rate (11.78 K/9 vs 7.92 K/9)
- Better walk rate (1.33 BB/9 vs 1.83 BB/9)
- Lower WHIP (0.737 vs 0.853)
- Pitched in the steroid era vs pitcher-friendly 1968
The verdict: Both seasons were absurd. Gibson dominated his era. Pedro transcended his. When you adjust for context, Pedro's 1.74 in 2000 might actually be more impressive than Gibson's 1.12 in 1968.
Other Notable Low-ERA Seasons
Greg Maddux — 1.56 ERA (1994)
In a strike-shortened season, Maddux went 16-6 with a 1.56 ERA in 202 innings. He allowed only 4 home runs all season and won his third straight Cy Young Award.
The 1994 season ended in August due to the players' strike, so Maddux didn't get a full year to pad stats. Still, his 1.56 ERA led the NL by a huge margin.
Dwight Gooden — 1.53 ERA (1985)
As a 20-year-old, Doc Gooden dominated with a 24-4 record and 1.53 ERA. He struck out 268 batters in 276.2 innings and won the Cy Young Award unanimously.
Gooden's 1985 season might be the best age-20 pitching performance ever.
Jacob deGrom — 1.70 ERA (2018)
DeGrom went 10-9 despite a 1.70 ERA because the Mets couldn't score runs. He won the Cy Young Award despite just 10 wins—the lowest total for a Cy Young winner in a non-shortened season.
His 1.70 ERA was the sixth-best since 1969 when the mound was lowered.
Why We'll Never See 0.96 Again
Pitchers don't pitch 300+ innings anymore. The game has changed:
- Pitch counts: Starters pulled after 100 pitches regardless of performance
- Five-man rotations: Less work per pitcher
- Specialized relievers: Closers and setup men protect leads
- Better hitters: Training, nutrition, and scouting have improved
- Smaller ballparks: More home runs than ever
In 1968, Gibson averaged 8.96 innings per start. In 2023, only one pitcher averaged over 7 innings per start.
The closest anyone's come to 1.00 ERA in the last 20 years is deGrom's 1.70 in 2018. And he only pitched 217 innings.
How to Read ERA Records
Raw ERA numbers lie without context. Here's what to look for:
1. League average ERA that year
A 2.50 ERA in 1968 (when league average was 2.98) is different than 2.50 in 2000 (when league average was 4.91).
2. Innings pitched
A 1.00 ERA in 100 innings is less impressive than 1.12 in 300 innings.
3. Era of baseball
Dead-ball era (pre-1920), Year of the Pitcher (1968), steroid era (1990s-2000s) all had wildly different scoring environments.
4. Park factors
Pitching half your games in Fenway (hitter-friendly) or Coors Field (absurdly hitter-friendly) makes low ERAs harder.
ERA+ is a stat that adjusts for league average and park factors. 100 is average. Pedro's 2000 season posted an ERA+ of 291—the highest ever for a pitcher with 200+ innings. Gibson's 1968 was 258.
The Verdict
Tim Keefe owns the all-time record at 0.86. Dutch Leonard's 0.96 will probably stand forever as the AL record. Bob Gibson's 1.12 changed baseball's rules.
But when you factor in context—league average, era, park, innings pitched—Pedro Martinez's 1.74 ERA in 2000 might be the most dominant pitching season baseball has ever seen.
Gibson beat his league average by 1.78 runs. Pedro beat his by 3.17 runs. Pedro faced designated hitters, pitched in the steroid era, and played half his games in Fenway Park. His WHIP of 0.737 will never be touched.
Whether you prefer Gibson's raw ERA number or Pedro's adjusted dominance comes down to whether you value absolute numbers or relative context.
Either way, we're probably never seeing another season like either of them.