▁winning ▁ 4 9 . ▁ ▁Until ▁ 2 0 0 2 , ▁home - field ▁advantage ▁in ▁the ▁World ▁Series ▁altern ated ▁from ▁year ▁to ▁year ▁between ▁the ▁National ▁League ▁and ▁American ▁League . ▁ ▁From ▁ 2 0 0 3 ▁to ▁ 2 0 1 6 , ▁home - field ▁advantage ▁was ▁given ▁to ▁the ▁league ▁that ▁won ▁that ▁year ' s ▁All - Star ▁Game . ▁ ▁Starting ▁in ▁ 2 0 1 7 , ▁home - field ▁advantage ▁is ▁awarded ▁to ▁the ▁league ▁champion ▁team ▁with ▁the ▁better ▁regular ▁season ▁win - loss ▁record . ▁ ▁P rec urs ors ▁to ▁the ▁modern ▁World ▁Series ▁( 1 8 5 7 – 1 9 0 2 ) ▁ ▁The ▁original ▁World ▁Series ▁ ▁Until ▁the ▁formation ▁of ▁the ▁American ▁Association ▁in ▁ 1 8 8 2 ▁as ▁a ▁second ▁major ▁league , ▁the ▁National ▁Association ▁of ▁Professional ▁Base ▁Ball ▁Play ers ▁( 1 8 7 1 – 1 8 7 5 ) ▁and ▁then ▁the ▁National ▁League ▁( f ounded ▁ 1 8 7 6 ) ▁represented ▁the ▁top ▁level ▁of ▁organized ▁baseball ▁in ▁the ▁United ▁States . ▁All ▁champion ships ▁were ▁awarded ▁to ▁the ▁team ▁with ▁the ▁best ▁record ▁at ▁the ▁end ▁of ▁the ▁season , ▁without ▁a ▁post season ▁series ▁being ▁played . ▁From ▁ 1 8 8 4 ▁to ▁ 1 8 9 0 , ▁the ▁National ▁League ▁and ▁the ▁American ▁Association ▁faced ▁each ▁other ▁in ▁a ▁series ▁of ▁games ▁at ▁the ▁end ▁of ▁the ▁season ▁to