P: 47 W: 22 D: 9 L: 16
Previously: Merthyr Town
Last meeting: 19 Dec 2000 — Merthyr Tydfil v Llanelli (1-2)
| Season | Date | Match | Result | Score | Competition |
|---|---|---|---|---|---|
| 1948-49 | 21 Aug 1948 | Llanelli v Merthyr Town | L | 0-1 | LEAGUE |
| 1948-49 | 28 Aug 1948 | Merthyr Town v Llanelli | L | 2-3 | LEAGUE |
| 1948-49 | 29 Sep 1949 | Llanelli v Merthyr Town | L | 2-3 | WELSH LC |
| 1950-51 | 21 Oct 1950 | Merthyr Tydfil v Llanelli | D | 2-2 | LEAGUE |
| 1950-51 | 20 Jan 1951 | Llanelli v Merthyr Tydfil | L | 2-6 | LEAGUE |
| 1951-52 | 25 Dec 1951 | Llanelli v Merthyr Tydfil | L | 2-3 | LEAGUE |
| 1951-52 | 26 Dec 1951 | Merthyr Tydfil v Llanelli | W | 7-3 | LEAGUE |
| 1952-53 | 25 Dec 1952 | Llanelli v Merthyr Tydfil | W | 2-0 | LEAGUE |
| 1952-53 | 26 Dec 1952 | Merthyr Tydfil v Llanelli | W | 9-2 | LEAGUE |
| 1953-54 | 19 Apr 1954 | Llanelli v Merthyr Tydfil | W | 2-0 | LEAGUE |
| 1953-54 | 20 Apr 1954 | Merthyr Tydfil v Llanelli | W | 4-1 | LEAGUE |
| 1967-68 | 23 Sep 1967 | Merthyr Tydfil v Llanelli | D | 1-1 | LEAGUE |
| 1967-68 | 13 Apr 1968 | Llanelli v Merthyr Tydfil | LEAGUE | ||
| 1968-69 | Llanelli v Merthyr Tydfil | LEAGUE | |||
| 1968-69 | 21 Apr 1969 | Merthyr Tydfil v Llanelli | D | 0-0 | LEAGUE |
| 1969-70 | Merthyr Tydfil v Llanelli | W | 3-2 | WELSH C 5R | |
| 1969-70 | Llanelli v Merthyr Tydfil | LEAGUE | |||
| 1970-71 | 10 Oct 1970 | Merthyr Tydfil v Llanelli | D | 1-1 | FA CUP |
| 1970-71 | 21 Nov 1970 | Llanelli v Merthyr Tydfil | W | 3-1 | LEAGUE |
| 1970-71 | 20 Mar 1971 | Merthyr Tydfil v Llanelli | D | 0-0 | LEAGUE |
| 1970-71 | 15 Oct 1971 | Llanelli v Merthyr Tydfil | L | 0-2 | FA CUP |
| 1971-72 | 04 Sep 1971 | Llanelli v Merthyr Tydfil | L | 0-3 | FA CUP |
| 1971-72 | 04 Dec 1971 | Llanelli v Merthyr Tydfil | W | 3-1 | LEAGUE |
| 1972-73 | 09 Dec 1972 | Merthyr Tydfil v Llanelli | W | 2-1 | LEAGUE |
| 1973-74 | 19 Aug 1973 | Llanelli v Merthyr Tydfil | W | 1-0 | LEAGUE |
| 1974-75 | Merthyr Tydfil v Llanelli | L | 0-2 | LEAGUE | |
| 1974-75 | Llanelli v Merthyr Tydfil | W | 1-0 | SA BRAINS CUP 3R | |
| 1974-75 | 29 Mar 1975 | Llanelli v Merthyr Tydfil | L | 1-3 | LEAGUE |
| 1975-76 | Llanelli v Merthyr Tydfil | L | 0-1 | LEAGUE | |
| 1975-76 | 23 Aug 1975 | Merthyr Tydfil v Llanelli | W | 2-1 | LEAGUE |
| 1976-77 | Llanelli v Merthyr Tydfil | L | 3-6 | FA CUP | |
| 1976-77 | 30 Oct 1976 | Llanelli v Merthyr Tydfil | W | 4-1 | LEAGUE |
| 1976-77 | 12 Mar 1977 | Merthyr Tydfil v Llanelli | W | 1-0 | LEAGUE |
| 1977-78 | Merthyr Tydfil v Llanelli | W | 3-1 | LEAGUE | |
| 1977-78 | 26 Nov 1977 | Llanelli v Merthyr Tydfil | W | 2-0 | LEAGUE |
| 1978-79 | Merthyr Tydfil v Llanelli | W | 2-1 | LEAGUE | |
| 1978-79 | Llanelli v Merthyr Tydfil | L | 0-2 | LEAGUE | |
| 1979-80 | Merthyr Tydfil v Llanelli | W | 1-0 | LEAGUE | |
| 1979-80 | 20 Jan 1980 | Llanelli v Merthyr Tydfil | D | 0-0 | LEAGUE |
| 1980-81 | 08 Nov 1980 | Llanelli v Merthyr Tydfil | W | 4-1 | LEAGUE |
| 1980-81 | 14 Feb 1981 | Merthyr Tydfil v Llanelli | L | 0-3 | SA BRAINS CUP SF |
| 1980-81 | 04 Mar 1981 | Merthyr Tydfil v Llanelli | L | 0-1 | LEAGUE |
| 1981-82 | 17 Oct 1981 | Merthyr Tydfil v Llanelli | D | 0-0 | LEAGUE |
| 1981-82 | 13 Feb 1982 | Llanelli v Merthyr Tydfil | W | 2-1 | LEAGUE |
| 1982-83 | 25 Sep 1982 | Llanelli v Merthyr Tydfil | W | 3-2 | LEAGUE |
| 1982-83 | 11 Dec 1982 | Merthyr Tydfil v Llanelli | L | 1-4 | LEAGUE |
| 1988-89 | 03 Dec 1988 | Llanelli v Merthyr Tydfil | D | 0-0 | LEAGUE |
| 1988-89 | 06 May 1989 | Merthyr Tydfil v Llanelli | D | 1-1 | LEAGUE |
| 2000-01 | 06 Dec 2000 | Llanelli v Merthyr Tydfil | W | 4-2 | FAW PCG |
| 2000-01 | 19 Dec 2000 | Merthyr Tydfil v Llanelli | L | 1-2 | FAW PCG |