<Table> <Tr> <Th> State ( linked to summaries below ) </Th> <Th colspan="3"> Incumbent </Th> <Th> Intent / Results </Th> <Th> Candidates ( listed alphabetically ) </Th> </Tr> <Tr> <Th> Senator </Th> <Th> Party </Th> <Th> Electoral history </Th> </Tr> <Tr> <Td> Arizona </Td> <Td> Flake , Jeff Jeff Flake </Td> <Td> Republican </Td> <Td> 2012 </Td> <Td> Incumbent running </Td> <Td> Deedra Abboud ( Democratic ) Jeff Flake ( Republican ) Doug Marks ( Libertarian ) Jim Moss ( Democratic ) Chris Russell ( Democratic ) Richard Sherzan ( Democratic ) Nicolas Tutora ( Republican ) Kelli Ward ( Republican ) </Td> </Tr> <Tr> <Td> California </Td> <Td> Feinstein , Dianne Dianne Feinstein </Td> <Td> Democratic </Td> <Td> 1992 ( special ) 1994 2000 2006 2012 </Td> <Td> Incumbent running </Td> <Td> Donald R. Adams ( Independent ) Topher Brennan ( Democratic ) Jerry Leon Carroll ( Independent ) Michael Eisen ( Independent ) Dianne Feinstein ( Democratic ) Tim Gildersleeve ( Independent ) Eugene Patterson Harris ( Democratic ) David Hildebrand ( Democratic ) Charles Junior Hodge ( Independent ) Timothy Charles Kalemkarian ( Republican ) Caren Lancona ( Republican ) Richard Thomas Mead ( Independent ) John Melendez ( Democratic ) Douglas Howard Pierce ( Democratic ) Joseph Sandberg Stephen James Schrader ( Republican ) Steve Stokes ( Democratic ) </Td> </Tr> <Tr> <Td> Connecticut </Td> <Td> Murphy , Chris Chris Murphy </Td> <Td> Democratic </Td> <Td> 2012 </Td> <Td> Incumbent running </Td> <Td> Ann - Marie Adams ( Democratic ) Matthew Corey ( Republican ) Chris Murphy ( Democratic ) Dominic Rapini ( Republican ) </Td> </Tr> <Tr> <Td> Delaware </Td> <Td> Carper , Tom Tom Carper </Td> <Td> Democratic </Td> <Td> 2000 2006 2012 </Td> <Td> Incumbent running </Td> <Td> Tom Carper ( Democratic ) Chuck Boyce ( Republican ) </Td> </Tr> <Tr> <Td> Florida </Td> <Td> Nelson , Bill Bill Nelson </Td> <Td> Democratic </Td> <Td> 2000 2006 2012 </Td> <Td> Incumbent running </Td> <Td> Joe Allen ( Independent ) Lateresa Ann Jones ( Republican ) Edward Janowski ( Independent ) Tamika Lyles ( Democratic ) Bill Nelson ( Democratic ) Marcia Roberta Thorne ( Republican ) Joe Wendt ( Libertarian ) </Td> </Tr> <Tr> <Td> Hawaii </Td> <Td> Hirono , Mazie Mazie Hirono </Td> <Td> Democratic </Td> <Td> 2012 </Td> <Td> Incumbent running </Td> <Td> Mazie Hirono ( Democratic ) </Td> </Tr> <Tr> <Td> Indiana </Td> <Td> Donnelly , Joe Joe Donnelly </Td> <Td> Democratic </Td> <Td> 2012 </Td> <Td> Incumbent running </Td> <Td> Mike Braun ( Republican ) Joe Donnelly ( Democratic ) Terry Henderson ( Republican ) Mark Hurt ( Republican ) Luke Messer ( Republican ) Todd Rokita ( Republican ) Kiel Richard Stone ( Republican ) Andrew Takami ( Republican ) Andrew U.D. Straw ( Disability Party ) </Td> </Tr> <Tr> <Td> Maine </Td> <Td> King , Angus Angus King </Td> <Td> Independent </Td> <Td> 2012 </Td> <Td> Incumbent running </Td> <Td> Angus King ( Independent ) Eric Brakey ( Republican ) </Td> </Tr> <Tr> <Td> Maryland </Td> <Td> Cardin , Ben Ben Cardin </Td> <Td> Democratic </Td> <Td> 2006 2012 </Td> <Td> Incumbent running </Td> <Td> Ben Cardin ( Democratic ) Sam Faddis ( Republican ) Richard `` Rikki '' Vaughn ( Democratic ) Debbie `` Rica '' Wilson ( Democratic ) </Td> </Tr> <Tr> <Td> Massachusetts </Td> <Td> Warren , Elizabeth Elizabeth Warren </Td> <Td> Democratic </Td> <Td> 2012 </Td> <Td> Incumbent running </Td> <Td> Elizabeth Warren ( Democratic ) Shiva Ayyadurai ( Republican ) Geoff Diehl ( Republican ) Mary Lindstrom ( Republican ) Darius Mitchell ( Republican ) Allen Waters ( Republican ) Heidi Wellman ( Republican ) James Devine ( Independent ) Joshua Ford ( Independent ) </Td> </Tr> <Tr> <Td> Michigan </Td> <Td> Stabenow , Debbie Debbie Stabenow </Td> <Td> Democratic </Td> <Td> 2000 2006 2012 </Td> <Td> Incumbent running </Td> <Td> John James ( Republican ) Robert P. Young Jr . ( Republican ) Craig Allen Smith ( Democratic ) Debbie Stabenow ( Democratic ) Marcia Squier ( independent ) </Td> </Tr> <Tr> <Td> Minnesota </Td> <Td> Klobuchar , Amy Amy Klobuchar </Td> <Td> Democratic </Td> <Td> 2006 2012 </Td> <Td> Incumbent running </Td> <Td> Amy Klobuchar ( Democratic ) Jim Newberger ( Republican ) </Td> </Tr> <Tr> <Td> Mississippi </Td> <Td> Wicker , Roger Roger Wicker </Td> <Td> Republican </Td> <Td> 2007 ( appointed ) 2008 ( special ) 2012 </Td> <Td> Incumbent running </Td> <Td> Jensen Bohren ( Democratic ) Roger Wicker ( Republican ) </Td> </Tr> <Tr> <Td> Missouri </Td> <Td> McCaskill , Claire Claire McCaskill </Td> <Td> Democratic </Td> <Td> 2006 2012 </Td> <Td> Incumbent running </Td> <Td> Angelica Earl ( Democratic ) Claire McCaskill ( Democratic ) Tony Monetti ( Republican ) Austin Petersen ( Republican )
<Table> <Tr> <Th> State ( linked to summaries below ) </Th> <Th colspan="3"> Incumbent </Th> <Th> Intent / Results </Th> <Th> Candidates ( listed alphabetically ) </Th> </Tr> <Tr> <Th> Senator </Th> <Th> Party </Th> <Th> Electoral history </Th> </Tr> <Tr> <Td> Arizona </Td> <Td> Flake , Jeff Jeff Flake </Td> <Td> Republican </Td> <Td> 2012 </Td> <Td> Incumbent running </Td> <Td> Deedra Abboud ( Democratic ) Jeff Flake ( Republican ) Doug Marks ( Libertarian ) Jim Moss ( Democratic ) Chris Russell ( Democratic ) Richard Sherzan ( Democratic ) Nicolas Tutora ( Republican ) Kelli Ward ( Republican ) </Td> </Tr> <Tr> <Td> California </Td> <Td> Feinstein , Dianne Dianne Feinstein </Td> <Td> Democratic </Td> <Td> 1992 ( special ) 1994 2000 2006 2012 </Td> <Td> Incumbent running </Td> <Td> Donald R. Adams ( Independent ) Topher Brennan ( Democratic ) Jerry Leon Carroll ( Independent ) Michael Eisen ( Independent ) Dianne Feinstein ( Democratic ) Tim Gildersleeve ( Independent ) Eugene Patterson Harris ( Democratic ) David Hildebrand ( Democratic ) Charles Junior Hodge ( Independent ) Timothy Charles Kalemkarian ( Republican ) Caren Lancona ( Republican ) Richard Thomas Mead ( Independent ) John Melendez ( Democratic ) Douglas Howard Pierce ( Democratic ) Joseph Sandberg Stephen James Schrader ( Republican ) Steve Stokes ( Democratic ) </Td> </Tr> <Tr> <Td> Connecticut </Td> <Td> Murphy , Chris Chris Murphy </Td> <Td> Democratic </Td> <Td> 2012 </Td> <Td> Incumbent running </Td> <Td> Ann - Marie Adams ( Democratic ) Matthew Corey ( Republican ) Chris Murphy ( Democratic ) Dominic Rapini ( Republican ) </Td> </Tr> <Tr> <Td> Delaware </Td> <Td> Carper , Tom Tom Carper </Td> <Td> Democratic </Td> <Td> 2000 2006 2012 </Td> <Td> Incumbent running </Td> <Td> Tom Carper ( Democratic ) Chuck Boyce ( Republican ) </Td> </Tr> <Tr> <Td> Florida </Td> <Td> Nelson , Bill Bill Nelson </Td> <Td> Democratic </Td> <Td> 2000 2006 2012 </Td> <Td> Incumbent running </Td> <Td> Joe Allen ( Independent ) Lateresa Ann Jones ( Republican ) Edward Janowski ( Independent ) Tamika Lyles ( Democratic ) Bill Nelson ( Democratic ) Marcia Roberta Thorne ( Republican ) Joe Wendt ( Libertarian ) </Td> </Tr> <Tr> <Td> Hawaii </Td> <Td> Hirono , Mazie Mazie Hirono </Td> <Td> Democratic </Td> <Td> 2012 </Td> <Td> Incumbent running </Td> <Td> Mazie Hirono ( Democratic ) </Td> </Tr> <Tr> <Td> Indiana </Td> <Td> Donnelly , Joe Joe Donnelly </Td> <Td> Democratic </Td> <Td> 2012 </Td> <Td> Incumbent running </Td> <Td> Mike Braun ( Republican ) Joe Donnelly ( Democratic ) Terry Henderson ( Republican ) Mark Hurt ( Republican ) Luke Messer ( Republican ) Todd Rokita ( Republican ) Kiel Richard Stone ( Republican ) Andrew Takami ( Republican ) Andrew U.D. Straw ( Disability Party ) </Td> </Tr> <Tr> <Td> Maine </Td> <Td> King , Angus Angus King </Td> <Td> Independent </Td> <Td> 2012 </Td> <Td> Incumbent running </Td> <Td> Angus King ( Independent ) Eric Brakey ( Republican ) </Td> </Tr> <Tr> <Td> Maryland </Td> <Td> Cardin , Ben Ben Cardin </Td> <Td> Democratic </Td> <Td> 2006 2012 </Td> <Td> Incumbent running </Td> <Td> Ben Cardin ( Democratic ) Sam Faddis ( Republican ) Richard `` Rikki '' Vaughn ( Democratic ) Debbie `` Rica '' Wilson ( Democratic ) </Td> </Tr> <Tr> <Td> Massachusetts </Td> <Td> Warren , Elizabeth Elizabeth Warren </Td> <Td> Democratic </Td> <Td> 2012 </Td> <Td> Incumbent running </Td> <Td> Elizabeth Warren ( Democratic ) Shiva Ayyadurai ( Republican ) Geoff Diehl ( Republican ) Mary Lindstrom ( Republican ) Darius Mitchell ( Republican ) Allen Waters ( Republican ) Heidi Wellman ( Republican ) James Devine ( Independent ) Joshua Ford ( Independent ) </Td> </Tr> <Tr> <Td> Michigan </Td> <Td> Stabenow , Debbie Debbie Stabenow </Td> <Td> Democratic </Td> <Td> 2000 2006 2012 </Td> <Td> Incumbent running </Td> <Td> John James ( Republican ) Robert P. Young Jr . ( Republican ) Craig Allen Smith ( Democratic ) Debbie Stabenow ( Democratic ) Marcia Squier ( independent ) </Td> </Tr> <Tr> <Td> Minnesota </Td> <Td> Klobuchar , Amy Amy Klobuchar </Td> <Td> Democratic </Td> <Td> 2006 2012 </Td> <Td> Incumbent running </Td> <Td> Amy Klobuchar ( Democratic ) Jim Newberger ( Republican ) </Td> </Tr> <Tr> <Td> Mississippi </Td> <Td> Wicker , Roger Roger Wicker </Td> <Td> Republican </Td> <Td> 2007 ( appointed ) 2008 ( special ) 2012 </Td> <Td> Incumbent running </Td> <Td> Jensen Bohren ( Democratic ) Roger Wicker ( Republican ) </Td> </Tr> <Tr> <Td> Missouri </Td> <Td> McCaskill , Claire Claire McCaskill </Td> <Td> Democratic </Td> <Td> 2006 2012 </Td> <Td> Incumbent running </Td> <Td> Angelica Earl ( Democratic ) Claire McCaskill ( Democratic ) Tony Monetti ( Republican ) Austin Petersen ( Republican )
names of republican senators up for reelection in 2018
names of republican senators up for reelection in 2018
Jeff Flake Roger Wicker
Jeff Flake Roger Wicker Deb Fischer Dean Heller Ted Cruz Orrin Hatch John Barrasso