| District | Incumbent | Results | Candidates |
| Location | 2017PVI | Representative | Party | Firstelected |
| California 1 | R+11 | Doug LaMalfa | Republican | 2012 | Incumbent re-elected. | ▌Y Doug LaMalfa (Republican) 54.9% ▌Audrey Denney (Democratic) 45.1% |
| California 2 | D+22 | Jared Huffman | Democratic | 2012 | Incumbent re-elected. | ▌Y Jared Huffman (Democratic) 77.0% ▌Dale Mensing (Republican) 23.0% |
| California 3 | D+5 | John Garamendi | Democratic | 2009 (special) | Incumbent re-elected. | ▌Y John Garamendi (Democratic) 58.1% ▌Charlie Schaupp (Republican) 41.9% |
| California 4 | R+10 | Tom McClintock | Republican | 2008 | Incumbent re-elected. | ▌Y Tom McClintock (Republican) 54.1% ▌Jessica Morse (Democratic) 45.9% |
| California 5 | D+21 | Mike Thompson | Democratic | 1998 | Incumbent re-elected. | ▌Y Mike Thompson (Democratic) 78.9% ▌Anthony Mills (Independent) 21.1% |
| California 6 | D+21 | Doris Matsui | Democratic | 2005 (special) | Incumbent re-elected. | ▌Y Doris Matsui (Democratic) 80.4% ▌Jrmar Jefferson (Democratic) 19.6% |
| California 7 | D+3 | Ami Bera | Democratic | 2012 | Incumbent re-elected. | ▌Y Ami Bera (Democratic) 55.0% ▌Andrew Grant (Republican) 45.0% |
| California 8 | R+9 | Paul Cook | Republican | 2012 | Incumbent re-elected. | ▌Y Paul Cook (Republican) 60.0% ▌Tim Donnelly (Republican) 40.0% |
| California 9 | D+8 | Jerry McNerney | Democratic | 2006 | Incumbent re-elected. | ▌Y Jerry McNerney (Democratic) 56.5% ▌Marla Livengood (Republican) 43.5% |
| California 10 | Even | Jeff Denham | Republican | 2010 | Incumbent lost re-election.New member elected.Democratic gain. | ▌Y Josh Harder (Democratic) 52.3% ▌Jeff Denham (Republican) 47.7% |
| California 11 | D+21 | Mark DeSaulnier | Democratic | 2014 | Incumbent re-elected. | ▌Y Mark DeSaulnier (Democratic) 74.1% ▌John Fitzgerald (Republican) 25.9% |
| California 12 | D+37 | Nancy Pelosi | Democratic | 1987 | Incumbent re-elected. | ▌Y Nancy Pelosi (Democratic) 86.8% ▌Lisa Remmer (Republican) 13.2% |
| California 13 | D+40 | Barbara Lee | Democratic | 1998 (special) | Incumbent re-elected. | ▌Y Barbara Lee (Democratic) 88.4% ▌Laura Wells (Green) 11.6% |
| California 14 | D+27 | Jackie Speier | Democratic | 2008 (special) | Incumbent re-elected. | ▌Y Jackie Speier (Democratic) 79.2% ▌Cristina Osmeña (Republican) 20.8% |
| California 15 | D+20 | Eric Swalwell | Democratic | 2012 | Incumbent re-elected. | ▌Y Eric Swalwell (Democratic) 73.0% ▌Rudy Peters (Republican) 27.0% |
| California 16 | D+9 | Jim Costa | Democratic | 2004 | Incumbent re-elected. | ▌Y Jim Costa (Democratic) 57.5% ▌Elizabeth Heng (Republican) 42.5% |
| California 17 | D+25 | Ro Khanna | Democratic | 2016 | Incumbent re-elected. | ▌Y Ro Khanna (Democratic) 75.3% ▌Ron Cohen (Republican) 24.7% |
| California 18 | D+23 | Anna Eshoo | Democratic | 1992 | Incumbent re-elected. | ▌Y Anna Eshoo (Democratic) 74.5% ▌Christine Russell (Republican) 25.5% |
| California 19 | D+24 | Zoe Lofgren | Democratic | 1994 | Incumbent re-elected. | ▌Y Zoe Lofgren (Democratic) 73.8% ▌Justin Aguilera (Republican) 26.2% |
| California 20 | D+23 | Jimmy Panetta | Democratic | 2016 | Incumbent re-elected. | ▌Y Jimmy Panetta (Democratic) 81.4% ▌Ronald Kabat (Independent) 18.6% |
| California 21 | D+5 | David Valadao | Republican | 2012 | Incumbent lost re-election.New member elected.Democratic gain. | ▌Y TJ Cox (Democratic) 50.4% ▌David Valadao (Republican) 49.6% |
| California 22 | R+8 | Devin Nunes | Republican | 2002 | Incumbent re-elected. | ▌Y Devin Nunes (Republican) 52.7% ▌Andrew Janz (Democratic) 47.3% |
| California 23 | R+14 | Kevin McCarthy | Republican | 2006 | Incumbent re-elected. | ▌Y Kevin McCarthy (Republican) 63.7% ▌Tatiana Matta (Democratic) 36.3% |
| California 24 | D+7 | Salud Carbajal | Democratic | 2016 | Incumbent re-elected. | ▌Y Salud Carbajal (Democratic) 58.6% ▌Justin Fareed (Republican) 41.4% |
| California 25 | Even | Steve Knight | Republican | 2014 | Incumbent lost re-election.Democratic gain. | ▌Y Katie Hill (Democratic) 54.4% ▌Steve Knight (Republican) 45.6% |
| California 26 | D+7 | Julia Brownley | Democratic | 2012 | Incumbent re-elected. | ▌Y Julia Brownley (Democratic) 61.9% ▌Antonio Sabàto Jr. (Republican) 38.1% |
| California 27 | D+16 | Judy Chu | Democratic | 2009 (special) | Incumbent re-elected. | ▌Y Judy Chu (Democratic) 79.2% ▌Bryan Witt (Democratic) 20.8% |
| California 28 | D+23 | Adam Schiff | Democratic | 2000 | Incumbent re-elected. | ▌Y Adam Schiff (Democratic) 78.4% ▌Johnny Nalbandian (Republican) 21.6% |
| California 29 | D+29 | Tony Cárdenas | Democratic | 2012 | Incumbent re-elected. | ▌Y Tony Cárdenas (Democratic) 80.6% ▌Benito Bernal (Republican) 19.4% |
| California 30 | D+18 | Brad Sherman | Democratic | 1996 | Incumbent re-elected. | ▌Y Brad Sherman (Democratic) 73.4% ▌Mark Reed (Republican) 26.6% |
| California 31 | D+8 | Pete Aguilar | Democratic | 2014 | Incumbent re-elected. | ▌Y Pete Aguilar (Democratic) 58.7% ▌Sean Flynn (Republican) 41.3% |
| California 32 | D+17 | Grace Napolitano | Democratic | 1998 | Incumbent re-elected. | ▌Y Grace Napolitano (Democratic) 68.8% ▌Joshua Scott (Republican) 31.2% |
| California 33 | D+16 | Ted Lieu | Democratic | 2014 | Incumbent re-elected. | ▌Y Ted Lieu (Democratic) 70.0% ▌Kenneth Wright (Republican) 30.0% |
| California 34 | D+35 | Jimmy Gomez | Democratic | 2017 (special) | Incumbent re-elected. | ▌Y Jimmy Gomez (Democratic) 72.5% ▌Kenneth Mejia (Green) 27.5% |
| California 35 | D+19 | Norma Torres | Democratic | 2014 | Incumbent re-elected. | ▌Y Norma Torres (Democratic) 69.4% ▌Christian Valiente (Republican) 30.6% |
| California 36 | D+2 | Raul Ruiz | Democratic | 2012 | Incumbent re-elected. | ▌Y Raul Ruiz (Democratic) 59.0% ▌Kimberlin Brown Pelzer (Republican) 41.0% |
| California 37 | D+37 | Karen Bass | Democratic | 2010 | Incumbent re-elected. | ▌Y Karen Bass (Democratic) 89.1% ▌Ron Bassilian (Republican) 10.9% |
| California 38 | D+17 | Linda Sánchez | Democratic | 2002 | Incumbent re-elected. | ▌Y Linda Sánchez (Democratic) 68.9% ▌Ryan Downing (Republican) 31.1% |
| California 39 | Even | Ed Royce | Republican | 1992 | Incumbent retired.New member elected.Democratic gain. | ▌Y Gil Cisneros (Democratic) 51.6% ▌Young Kim (Republican) 48.4% |
| California 40 | D+33 | Lucille Roybal-Allard | Democratic | 1992 | Incumbent re-elected. | ▌Y Lucille Roybal-Allard (Democratic) 77.3% ▌Rodolfo Barragan (Green) 22.7% |
| California 41 | D+12 | Mark Takano | Democratic | 2012 | Incumbent re-elected. | ▌Y Mark Takano (Democratic) 65.1% ▌Aja Smith (Republican) 34.9% |
| California 42 | R+9 | Ken Calvert | Republican | 1992 | Incumbent re-elected. | ▌Y Ken Calvert (Republican) 56.5% ▌Julia Peacock (Democratic) 43.5% |
| California 43 | D+29 | Maxine Waters | Democratic | 1990 | Incumbent re-elected. | ▌Y Maxine Waters (Democratic) 77.7% ▌Omar Navarro (Republican) 22.3% |
| California 44 | D+35 | Nanette Barragán | Democratic | 2016 | Incumbent re-elected. | ▌Y Nanette Barragán (Democratic) 68.3% ▌Aja Brown (Democratic) 31.7% |
| California 45 | R+3 | Mimi Walters | Republican | 2014 | Incumbent lost re-election.Democratic gain. | ▌Y Katie Porter (Democratic) 52.1% ▌Mimi Walters (Republican) 47.9% |
| California 46 | D+15 | Lou Correa | Democratic | 2016 | Incumbent re-elected. | ▌Y Lou Correa (Democratic) 69.1% ▌Russell Lambert (Republican) 30.9% |
| California 47 | D+13 | Alan Lowenthal | Democratic | 2012 | Incumbent re-elected. | ▌Y Alan Lowenthal (Democratic) 64.9% ▌John Briscoe (Republican) 35.1% |
| California 48 | R+4 | Dana Rohrabacher | Republican | 1988 | Incumbent lost re-election.Democratic gain. | ▌Y Harley Rouda (Democratic) 53.6% ▌Dana Rohrabacher (Republican) 46.4% |