| Election Name: | 1948 United States Senate election in South Dakota |
| Country: | South Dakota |
| Flag Year: | 1909 |
| Type: | presidential |
| Ongoing: | no |
| Previous Election: | 1942 United States Senate election in South Dakota |
| Previous Year: | 1942 |
| Next Election: | 1954 United States Senate election in South Dakota |
| Next Year: | 1954 |
| Election Date: | November 2, 1948 |
| Image1: | File:Rep. Karl Mundt, Repub., of S.D., 2-21-40 LCCN2016877155 (cropped).jpg |
| Nominee1: | Karl E. Mundt |
| Party1: | Republican Party (United States) |
| Popular Vote1: | 144,084 |
| Percentage1: | 59.33% |
| Nominee2: | John A. Engel |
| Party2: | Democratic Party (United States) |
| Popular Vote2: | 98,749 |
| Percentage2: | 40.67% |
| Map Size: | 240px |
| U.S. Senator | |
| Before Election: | Vera C. Bushfield |
| Before Party: | Republican Party (United States) |
| After Election: | Karl E. Mundt |
| After Party: | Republican Party (United States) |
The 1948 United States Senate election in South Dakota took place on November 2, 1948. Incumbent Republican Senator Harlan J. Bushfield, suffering from poor health, declined to run for re-election. On September 27, 1948, he died in office; his wife, Vera C. Bushfield, was appointed to succeed him. Congressman Karl E. Mundt easily won the Republican primary and advanced to the general election, where he was opposed by Democratic nominee John A. Engel, an attorney. Hundt defeated Engel in a landslide.
John A. Engel, an attorney from Avon,[1] was the only Democratic candidate to file for the U.S. Senate and he won the nomination unopposed, thereby removing it from the primary election ballot.[2]