| The 17th Republican National Convention assembled in the Coliseum in Chicago IL. Each state received two delegates per electoral vote.
The leading contenders in the primaries were Leonard Wood, Hiram Johnson, Frank Lowden, and Herbert Hoover. Wood was the 'organization' candidate, working in the state conventions to win delegates. He entered eleven primaries and won six of them. Although in late spring Wood's lead in the race for delegates appeared insurmountable, members of the U.S. Senate were shocked by his lavish use of campaign money. Sen. Borah began an investigation into the expenditures of all candidates. It came to light that Wood spent $1.5 million on the nomination, including large sums of cash that Borah considered to be bribes for purchasing delegates. The Senate hearings crushed Wood's campaign - in the last primary (North Carolina), he lost roughly 3:1 to Hiram Johnson.
When the convention assembled, the leading contenders were unable to break 1/3 of the total delegate vote, far short of a majority. Finally on the tenth ballot leading Republicans decided to break the deadlock by supporting a second-tier candidate from the primaries, U.S. Senator Warren G. Harding (OH). Gov. Calvin Coolidge (MA) was selected for VP over Irvine Lenroot, the choice of the men who brokered the deal to support Harding.
Keynote speaker: U.S. Senator Henry C. Lodge MA
| Presidential Balloting, RNC 1920 |
| Contender: Ballot | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 before shifts | 10 after shifts |
| Warren G. Harding | 65.5 | 59 | 58.5 | 61.5 | 78 | 89 | 105 | 133 | 374.5 | 644.7 | 692.2 |
| Leonard Wood | 287.5 | 289.5 | 303 | 314.5 | 299 | 311.5 | 312 | 299 | 249 | 181.5 | 156 |
| Frank O. Lowden | 211.5 | 259.5 | 282.5 | 289 | 303 | 311.5 | 311.5 | 307 | 121.5 | 28 | 11 |
| Hiram W. Johnson | 133.5 | 146 | 148 | 140.5 | 133.5 | 110 | 99.5 | 87 | 82 | 80.8 | 80.8 |
| William C. Sproul | 84 | 78.5 | 79.5 | 79.5 | 82.5 | 77 | 76 | 76 | 78 | 0 | 0 |
| Nicholas M. Butler | 69.5 | 41 | 25 | 20 | 4 | 4 | 2 | 2 | 2 | 2 | 2 |
| Calvin Coolidge | 34 | 32 | 27 | 25 | 29 | 28 | 28 | 30 | 28 | 5 | 5 |
| Robert M. LaFollette | 24 | 24 | 24 | 22 | 24 | 24 | 24 | 24 | 24 | 24 | 24 |
| Jeter C. Pritchard | 21 | 10 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Miles Poindexter | 20 | 15 | 15 | 15 | 15 | 15 | 15 | 15 | 14 | 2 | 0 |
| Howard Sutherland | 17 | 15 | 9 | 3 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |
| Herbert C. Hoover | 5.5 | 5.5 | 5.5 | 5 | 6 | 5 | 4 | 5 | 6 | 10.5 | 9.5 |
| Scattering | 11 | 9 | 7 | 9 | 9 | 9 | 6 | 6 | 5 | 5.5 | 3.5 |
Ninth Ballot map:
Red states voted for Harding; light red states shifted to him on the 9th ballot.
Blue states voted for Wood.
Green states voted for Lowden.
White states voted for other contenders. | 
644 (37.40%)
