| Year | A C No. | Constituency Name | Category | Winner | Gender | Party | Votes | Runner Up | Gender | Party | Votes |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1957 | 21 | Kunnathur | (SC) | Madhavan Pillai P. R. | M | CPI | 41569 | Govindan R. | M | CPI | 37321 |
| 1960 | 21 | Kunnathur | GEN | G. Candras Ekhara Pillai | M | INC | 51101 | P. C. Adichen | M | CPI | 49253 |
| 1965 | 112 | Kunnathur | (SC) | T. Krishnan | M | KC | 15734 | T. Kesavan | M | CPI | 12297 |
| 1967 | 112 | Kunnathur | (SC) | K . C . S . Sastry | M | IND | 26510 | T . Kesavan | M | INC | 13559 |
| 1970 | 112 | Kunnathur | (SC) | Sathyapalan | M | RSP | 29008 | Onamplam Prabhakaran | M | IND | 17528 |
| 1977 | 120 | Kunnathur | (SC) | Kallada Narayanan | M | RSP | 43347 | C.K. Thankappan | M | CPM | 25103 |
| 1980 | 120 | Kunnathur | (SC) | Kallada Narayanan | M | RSP | 40582 | Kottakkuzhy Sukumaran | M | JNP | 29686 |
| 1982 | 120 | Kunnathur | (SC) | Kottakuzhi Sukumaran | M | IND | 39992 | Kallada Narayanan | M | RSP | 36602 |
| 1987 | 120 | Kunnathur | (SC) | T. Nanu Master | M | RSP | 52447 | K. K. Balakrishnan | M | INC | 41794 |
| 1991 | 120 | Kunnathur | (SC) | T. Nanoomaster | M | RSP | 56064 | V. Sasidharan | M | INC | 53462 |
| 1996 | 120 | Kunnathur | (SC) | T. Nanoo | M | RSP | 51697 | Visalakshy | F | INC | 46934 |
| 2001 | 120 | Kunnathur | (SC) | Kovoor Kunjumon | M | RSP | 60827 | Pandalam Sudhakaran | M | INC | 57341 |
| 2006 | 120 | Kunnathur | (SC) | Kovoor Kunjumon | M | RSP | 65011 | P Ramabhadran | M | INC | 42438 |
| 2011 | 118 | Kunnathur | (SC) | Kovoor Kunjumon | M | RSP | 71923 | P.K. Ravi | M | INC | 59835 |
| 2016 | 118 | Kunnathur | (SC) | Kovoor Kunjumon | M | IND | 75725 | Ullas Kovur | M | RSP | 55196 |
| 2021 | 118 | Kunnathur | (SC) | Kovoor Kunjumon | M | IND | 69436 | Ullas Kovur | M | RCP | 66646 |