The National League and the American Association faced each other in a World's Championship Series at the end of the season to determine an overall champion.
 
No champion declared
z: best record, c: conference winner, y: division winner, w: wildcard, x: clinched playoff spot
The Series commenced on October 17 and concluded on October 28. The weather had become progressively worse as the Series wore on, and prior to Game 7, the two managers agreed that this would be the final game, and if Louisville won the game to square the Series at 3–3–1 (which they did), that there would be a deciding championship game the following spring. Unfortunately for that plan, the championship game was never held. Disputes arose between the National League and the American Association during the winter about the redistribution of players following the dissolution of the Players' League. The Association ended its relationship with the League before the spring of 1891, so the anticipated championship game was canceled, and no World Series was held in 1891

World's Championship Series

Best of 7-game series
Date    OpponentResultScoreSeries
10/17vs BrooklynL  0-9
8
0-1
10/18vs BrooklynL  3-5 0-2
10/20vs BrooklynT  7-7
8
0-2
10/21vs BrooklynW  5-4 1-2
10/25at BrooklynL  2-7 1-3
10/27at BrooklynW  9-8 2-3
10/28at BrooklynW  6-2 3-3