Understanding how favorites and underdogs perform in Major League Baseball is one of the most important foundations of sports betting. Many bettors assume that betting favorites is the safest strategy, while others believe underdogs provide better long-term value.
To evaluate these assumptions, we analyzed MLB betting results from 2004 through 2024, covering more than two decades of games.
This historical data provides insight into how often favorites win, whether underdogs offer better value, and how the betting market has performed over time.
How Often Do MLB Favorites Win?
Historical results show that favorites win the majority of MLB games. From 2004 through 2024, favorites produced the following straight-up record:
Favorites (Moneyline)
30008–21514
Win Rate: 58.2%
ROI: -1.8%
Profit/Loss: -$141,209
At first glance, a 58.2% win rate may seem like a strong betting strategy. However, sportsbooks price favorites at higher odds to reflect their increased probability of winning.
Because of these higher prices, blindly betting every MLB favorite historically produced a negative return on investment of approximately -1.8%.
This illustrates an important principle in sports betting: win percentage alone does not determine profitability. Even strategies that win more than half the time can lose money if the betting prices are too expensive.
How Often Do MLB Underdogs Win?
Underdogs naturally win fewer games overall, but they benefit from more favorable betting odds.
Based on the same dataset, MLB underdogs have won approximately:
Underdogs
21514–30008
Win Rate: 41.8%
ROI: -3.2%
Profit/Loss: -$164,753
Although underdogs win less frequently, their higher payouts partially offset the lower win rate.
However, like favorites, blindly betting every underdog also results in a negative long-term return.
This suggests the MLB betting market has historically been fairly efficient, making it difficult to profit without more advanced situational analysis.
Key Takeaways
The long-term data from more than 50,000 MLB games since 2004 reveals several important insights:
- Favorites win about 58% of games but still produce a negative ROI.
- Underdogs win about 42% of games, also with a negative ROI.
- The betting market is generally efficient over large sample sizes.
- Profitable betting strategies usually require situational edges rather than broad categories.
This is why many professional bettors focus on specific situations, such as travel fatigue, bullpen usage, or pitching mismatches, rather than simply betting favorites or underdogs.
Why Underdogs Can Offer Value
Underdogs win fewer games overall, but they receive more favorable odds.
Because of this pricing difference, some betting strategies focus on identifying situations where underdogs may be undervalued by the market.
Historically, MLB underdogs have won roughly 41.8% of games, but their payouts can sometimes compensate for the lower win rate.
However, blindly betting every underdog is also not a profitable long-term strategy. The market typically adjusts lines to balance betting action and maintain sportsbook margins.
Runline Performance: Favorites vs Underdogs
The runline is baseball’s equivalent of a point spread.
Most MLB runlines are set at -1.5 runs for favorites and +1.5 runs for underdogs.
Since 2004, runline results have shown a clear pattern:
Favorites ATS (Runline)
18979–25285 (42.9%)
This means runline favorites cover the spread less than half the time.
Conversely, runline underdogs cover significantly more often, hitting around 57.1% of games.
However, once betting odds are accounted for, the overall return still tends to be negative when betting blindly on either side.
What These Results Mean for Bettors
The historical data suggests several important lessons:
1. Favorites win often but are expensive.
Because sportsbooks adjust odds heavily toward favorites, blindly betting them tends to produce long-term losses.
2. Underdogs cover runlines more frequently.
The +1.5 run advantage helps underdogs perform better against the spread.
3. Market efficiency matters.
Sportsbooks price lines in ways that generally prevent simple strategies from producing consistent profits.
For bettors, the key takeaway is that success usually comes from identifying situational edges rather than betting broad categories like favorites or underdogs.
Situational MLB Betting Angles
While overall favorite vs underdog results are fairly efficient, certain situations can produce different outcomes.
Examples include:
- Teams playing after extra-inning games
- Bounce-back spots after blowout losses
- Travel fatigue after long road trips
- Pitching mismatch scenarios
These situations can sometimes create temporary inefficiencies in the betting market.
We explore several of these angles in more detail in our MLB betting research:
- MLB Runline Betting Trends
- MLB Teams After Scoring 10+ Runs
- MLB Teams After Extra-Inning Games
- MLB Teams After Blowout Loss Betting Results Since 2004
Final Thoughts
The long-term data shows that neither favorites nor underdogs provide an automatic betting edge.
Instead, profitable betting typically requires careful analysis of situational factors, pitching matchups, and market pricing.
Historical research like this helps bettors understand how the market behaves and where potential opportunities may exist.
As the MLB season continues to evolve, keeping track of these trends can provide valuable context when evaluating betting opportunities.
