U.S. Senate elections in Iowa
Elections won
R 26 · D 1339 Senate elections since 1914
Last decided by
12.0 pts2022, Charles E. Grassley over Michael Franken
Closest ever
0.08 pts1924, Smith W. Brookhart over Daniel F. Steck
Longest streak
7 in a rowRepublican, 1914–1930
Next election
2026Tuesday, November 3, 2026
Iowa's U.S. Senate seats are held by Republican Charles E. Grassley and Republican Joni Ernst; Grassley won the most recent race by 12.0 points in 2022. Grassley has held one seat since 1980 and Ernst the other since 2014. The 2022 race put Grassley ahead of Michael Franken, 12.0 points clear. Across 39 elections since 1914, Republicans have won 26 and Democrats 13. Of those, the closest was 1924, decided by 0.08 points; the widest 1992, by 42.4 points.
Charles E. Grassley R 681,501 · Michael Franken D 533,330
Charles E. Grassley R 926,007 · Patty Judge D 549,460 · Charles Aldrich L 41,794 · Jim Hennager N 17,649 · +1 more
Joni Ernst R 588,575 · Bruce Braley D 494,370 · Rick Stewart I 26,815 · Douglas Butzier L 8,232 · +2 more
Tom Harkin D 941,665 · Christopher Reed R 560,006
Charles E. Grassley R 1,038,175 · Arthur Small D 412,365 · Christy Ann Welty L 15,218 · Daryl A. Northrop G 11,121 · +1 more
Tom Harkin D 554,278 · Greg Ganske R 447,892 · Timothy A. Harthan G 11,340 · Richard J. Moore L 8,864
Charles E. Grassley R 648,480 · David Osterberg D 289,049 · Susan Marcus N 7,561 · Margaret Trowe S 2,542
Tom Harkin D 634,166 · Jim Lightfoot R 571,807 · Sue Atkinson N 9,768 · Fred Gratson N 4,248 · +2 more
Charles E. Grassley R 899,761 · Jean Lloyd-Jones D 351,561 · Stuart Zimmerman N 16,403 · Sue Atkinson 6,277 · +5 more
Tom Harkin D 535,975 · Thomas J. Tauke R 446,869
Charles E. Grassley R 683,014 · John Culver D 581,545 · Garry de Young B 5,858 · Robert V Hengerer L 4,233 · +1 more
Jack Miller R 522,339 · E. B. Smith D 324,114 · Robert D. Dilley A 3,826 · Charles H. Day I 3,050 · +2 more
Bourke B. Hickenlooper R 431,364 · E. B. Smith D 376,602
Jack Miller R 642,463 · Herschel C. Loveless D 595,119
Bourke B. Hickenlooper R 635,499 · R. M. Evans D 543,156
Bourke B. Hickenlooper R 470,613 · Albert J. Loveland D 383,766 · Z. Everett Kellum P 3,273 · Ernest J. Seemann D 571 · +1 more
Guy M. Gilette D 578,226 · George A. Wilson R 415,778 · Seymour Pitcher P 3,387 · Z. Everett Kellum P 2,580 · +1 more
Bourke B. Hickenlooper R 523,963 · Guy M. Gilette D 494,229 · W. S. Bowden P 2,751 · C. W. Drescher S 744
George A. Wilson R 410,383 · Clyde L. Herring D 295,194 · M. M. Heptonstall P 1,461 · Ernest J. Seemann P 821
Guy M. Gilette D 413,788 · Lester J. Dickinson R 410,983 · George F. Buresh F 4,723 · Raymond E. Hanke P 1,525 · +1 more
Guy M. Gillette D 536,075 · Berry F. Halden R 478,521
Clyde L. Herring D 539,555 · Lester J. Dickinson R 503,635 · George F. Buresh F 25,567 · John B. Hammond P 1,726 · +1 more
Lewis Murphy D 538,422 · Henry Field R 399,929 · Smith W. Brookhart P 43,174 · T. S. McCrill S 11,076 · +2 more
Lester J. Dickinson R 307,613 · Daniel F. Steck D 235,186 · Arthur A. Wells I 2,668 · L. E. Eickelberg I 1,045
Smith W. Brookhart R 323,409 · Claude R. Porter D 247,869
Smith W. Brookhart R 447,706 · Daniel F. Steck D 446,951 · Luther Brewer R 1,124 · L. E. Eickelberg I 535
Smith W. Brookhart R 389,751 · Clyde L. Herring D 227,833
Albert B. Cummins R 528,499 · Claude R. Porter D 322,015 · H. W. Cowles F 9,020 · Arthur S. Dowler S 933
William S. Kenyon R 230,264 · Charles R. Keyes D 121,830
Albert B. Cummins R 205,832 · Maurice Connolly D 167,251 · Otis L. Spurgeon I 24,490 · Casper Schenk P 15,058 · +2 more