| State | Senator | Party | Reelect |
| Alabama | Richard Shelby | Republican | 2016 |
| Alabama | Jeff Sessions | Republican | 2014 |
| Alaska | Lisa Murkowski | Republican | 2016 |
| Alaska | Mark Begich | Democratic | 2014 |
| Arizona | John McCain | Republican | 2016 |
| Arizona | Jeff Flake | Republican | 2018 |
| Arkansas | Mark Pryor | Democratic | 2014 |
| Arkansas | John Boozman | Republican | 2016 |
| California | Dianne Feinstein | Democratic | 2018 |
| California | Barbara Boxer | Democratic | 2016 |
| Colorado | Mark Udall | Democratic | 2014 |
| Colorado | Michael Bennet | Democratic | 2016 |
| Connecticut | Richard Blumenthal | Democratic | 2016 |
| Connecticut | Chris Murphy | Democratic | 2018 |
| Delaware | Tom Carper | Democratic | 2018 |
| Delaware | Chris Coons | Democratic | 2014 |
| Florida | Bill Nelson | Democratic | 2018 |
| Florida | Marco Rubio | Republican | 2016 |
| Georgia | Saxby Chambliss | Republican | 2014 |
| Georgia | Johnny Isakson | Republican | 2016 |
| Hawaii | Brian Schatz | Democratic | 2016 |
| Hawaii | Mazie Hirono | Democratic | 2018 |
| Idaho | Mike Crapo | Republican | 2016 |
| Idaho | Jim Risch | Republican | 2014 |
| Illinois | Dick Durbin | Democratic | 2014 |
| Illinois | Mark Kirk | Republican | 2016 |
| Indiana | Dan Coats | Republican | 2016 |
| Indiana | Joe Donnelly | Democratic | 2018 |
| Iowa | Chuck Grassley | Republican | 2016 |
| Iowa | Tom Harkin | Democratic | 2014 |
| Kansas | Pat Roberts | Republican | 2014 |
| Kansas | Jerry Moran | Republican | 2016 |
| Kentucky | Mitch McConnell | Republican | 2014 |
| Kentucky | Rand Paul | Republican | 2016 |
| Louisiana | Mary Landrieu | Democratic | 2014 |
| Louisiana | David Vitter | Republican | 2016 |
| Maine | Susan Collins | Republican | 2014 |
| Maine | Angus King | Independent | 2018 |
| Maryland | Barbara Mikulski | Democratic | 2016 |
| Maryland | Ben Cardin | Democratic | 2018 |
| Massachusetts | Elizabeth Warren | Democratic | 2018 |
| Massachusetts | Ed Markey | Democratic | 2014 |
| Michigan | Carl Levin | Democratic | 2014 |
| Michigan | Debbie Stabenow | Democratic | 2018 |
| Minnesota | Amy Klobuchar | Democratic | 2018 |
| Minnesota | Al Franken | Democratic | 2014 |
| Mississippi | Thad Cochran | Republican | 2014 |
| Mississippi | Roger Wicker | Republican | 2018 |
| Missouri | Claire McCaskill | Democratic | 2018 |
| Missouri | Roy Blunt | Republican | 2016 |
| Montana | Jon Tester | Democratic | 2018 |
| Montana | John Walsh | Democratic | 2014 |
| Nebraska | Mike Johanns | Republican | 2014 |
| Nebraska | Deb Fischer | Republican | 2018 |
| Nevada | Harry Reid | Democratic | 2016 |
| Nevada | Dean Heller | Republican | 2018 |
| New Hampshire | Jeanne Shaheen | Democratic | 2014 |
| New Hampshire | Kelly Ayotte | Republican | 2016 |
| New Jersey | Bob Menendez | Democratic | 2018 |
| New Jersey | Cory Booker | Democratic | 2014 |
| New Mexico | Tom Udall | Democratic | 2014 |
| New Mexico | Martin Heinrich | Democratic | 2018 |
| New York | Chuck Schumer | Democratic | 2016 |
| New York | Kirsten Gillibrand | Democratic | 2018 |
| North Carolina | Richard Burr | Republican | 2016 |
| North Carolina | Kay Hagan | Democratic | 2014 |
| North Dakota | John Hoeven | Republican | 2016 |
| North Dakota | Heidi Heitkamp | Democratic | 2018 |
| Ohio | Sherrod Brown | Democratic | 2018 |
| Ohio | Rob Portman | Republican | 2016 |
| Oklahoma | Jim Inhofe | Republican | 2014 |
| Oklahoma | Tom Coburn | Republican | 2016 |
| Oregon | Ron Wyden | Democratic | 2016 |
| Oregon | Jeff Merkley | Democratic | 2014 |
| Pennsylvania | Bob Casey | Democratic | 2018 |
| Pennsylvania | Pat Toomey | Republican | 2016 |
| Rhode Island | Jack Reed | Democratic | 2014 |
| Rhode Island | Sheldon Whitehouse | Democratic | 2018 |
| South Carolina | Lindsey Graham | Republican | 2014 |
| South Carolina | Tim Scott | Republican | 2016 |
| South Dakota | Tim Johnson | Democratic | 2014 |
| South Dakota | John Thune | Republican | 2016 |
| Tennessee | Lamar Alexander | Republican | 2014 |
| Tennessee | Bob Corker | Republican | 2018 |
| Texas | John Cornyn | Republican | 2014 |
| Texas | Ted Cruz | Republican | 2018 |
| Utah | Orrin Hatch | Republican | 2018 |
| Utah | Mike Lee | Republican | 2016 |
| Vermont | Patrick Leahy | Democratic | 2016 |
| Vermont | Bernie Sanders | Independent | 2018 |
| Virginia | Mark Warner | Democratic | 2014 |
| Virginia | Tim Kaine | Democratic | 2018 |
| Washington | Patty Murray | Democratic | 2016 |
| Washington | Maria Cantwell | Democratic | 2018 |
| West Virginia | Jay Rockefeller | Democratic | 2014 |
| West Virginia | Joe Manchin | Democratic | 2018 |
| Wisconsin | Ron Johnson | Republican | 2016 |
| Wisconsin | Tammy Baldwin | Democratic | 2018 |
| Wyoming | Mike Enzi | Republican | 2014 |
| Wyoming | John Barrasso | Republican | 2018 |
Current Senate