As described above, when you bet on sports like baseball, football or basketball, you are usually engaging in "fixed-odds betting." That means whatever the odds are when you place your bet, that will determine your payout if you win. With pari-mutuel wagering, it doesn't matter what the odds are when you place your bet. All that matters is what they are when betting closes and the race begins. Those are the odds that determine your payout if you are a winner. See above for more explanation of what makes pari-mutuel wagering unique.