| Round of 32 | ||||
| Eastern Bracket | ||||
| 5/14/45 | Brookhattan | 3 : 1 (aet) | New York Americans | |
| 3/18/45 | Brooklyn Hispano | 2 : 0 | German American AC | |
| 3/11/45 | Brooklyn Wanderers | 4 : 3 | Eintracht SC (NYC) | |
| 5/14/45 | Kearny Irish | 2 : 1 | Kearny Scots | |
| 4/1/45 | Baltimore Americans | 4 : 0 | Ruggiero SC (Bal.) | |
| 3/4/45 | Baltimore SC | 11 : 0 | Phoenix SC (Phi.) | |
| Philadelphia Americans | ||||
| Philadelphia Nationals | ||||
| Western Bracket | ||||
| 4/1/45 | Slovak SC (Chi.) | 1 : 0 | Sparta (Chi.) | |
| 4/1/45 | Viking AA (Chi.) | 2 : 1 | Hakoah Center (Chi.) | |
| 3/11/45 | Cleveland Americans | 11 : 2 | Rochester Celtics | |
| 5/2/45 | Gallatin (W. Pa.) | 3 : 0 | Morgan Strasser (W. Pa.) | |
| United German Americans (Det.) | ||||
| ??? | ||||
| 4/1/45 |
Raftery Painters (St. L) | 5 : 3 |
National Slug (St. L) | |
| Croatian Eagles (Mil.) | bye | Only Wisconsin Entry | ||
| Round of 16 | ||||
| Eastern Bracket | ||||
| 5/20/45 | Brookhattan | 2 : 1 | Kearny Irish | |
| 5/13/45 | Brooklyn Hispano | 4 : 3 (aet) | Brooklyn Wanderers | |
| 5/13/45 | Philadelphia Americans | 3 : 2 | Philadelphia Nationals | |
| 4/8/45 | Baltimore Americans | 1 : 0 | Baltimore SC | |
| Western Bracket | ||||
| 4/29/45 | Viking AA | 4 : 2 (aet) | Slovak SC | |
| 5/6/45 | Raftery Painters | 4 : 1 | Croatian Eagles | |
| United German Americans | ||||
| 5/13/45 | Cleveland Americans | 2 : 1 (aet) | Gallatin | |
| Quarterfinals | ||||
| 5/25/45 | Brooklyn Hispano | 4 : 3 | Philadelphia Americans | |
| 5/25/45 | Brookhattan | 3 : 2 | Baltimore Americans | |
| 5/27/45 | Viking A.A. | 3 : 6 |
Raftery Painters | |
| 5/27/45 | United German Americans | 1 : 2 | Cleveland Americans | |
| Semifinals | ||||
| 6/4/45 | Brookhattan | 5 : 4(aet) | Brooklyn Hispano | |
| 6/3/45 | Raftery Painters | 0 : 2 | Cleveland Americans | |
| Final | ||||
| First Leg – Starlight Park – Bronx, New York | ||||
| 6/10/45 | Brookhattan | 4 : 1 | Cleveland Americans | |
| Second Leg -at Shaw Field – Cleveland, Ohio | ||||
| 6/16/45 | Cleveland Americans | 1 : 2 | Brookhattan | |
| Brookhattan win National Challenge Cup on 6-2 aggregate | ||||
| KEY – w/o – Walkover, R – Replay, 1L – 1st Leg, 2L – 2nd Leg, 3L – 3rd Leg | ||||