| MacArthur | 1940 | Pot 8 o's系 |
| Machiavellian | 1987 | Mr. Prospector系 |
| Macho Uno | 1998 | Himyar系 |
| Mafosta | 1942 | Fair Trial系 |
| Magesterial | 1977 | Northern Dancer系 |
| Magpie | 1914 | Hampton系 |
| Mahmoud | 1933 | Blenheim系 |
| (アラ) Mahmoud Mirza | 1851 | Arab父系 |
| (アラ) Mahnagi Sbeli | ---- | Arab父系 |
| Majestic Light | 1973 | Raise a Native系 |
| Majestic Prince | 1966 | Raise a Native系 |
| Majestic Warrior | 2005 | Bold Ruler系 |
| Major Portion | 1955 | Fair Trial系 |
| Malibu Moon | 1997 | Bold Ruler系 |
| Maltster | 1897 | St. Simon系 |
| (アラ) Managi Sibeli | ---- | Arab父系 |
| Mandalus | 1974 | Fair Trial系 |
| Mandamus | 1960 | Fair Trial系 |
| Manila | 1983 | Lyphard系 |
| Manna | 1922 | Phalaris系 |
| Man o' War | 1917 | Matchem系 |
| Maori King | 1906 | St. Simon系 |
| Marabou | 1931 | Pot 8 o's系 |
| Marathon | 1904 | Bend Or系 |
| Maravedis | 1931 | St. Simon系 |
| March Along | 1917 | Swynford系 |
| Marco | 1892 | Matchem系 |
| Marconigram | 1925 | Pot 8 o's系 |
| Marcovil | 1903 | Matchem系 |
| Marju | 1988 | Northern Dancer系 |
| Mark of Esteem | 1993 | Mill Reef系 |
| Mark-Ye-Well | 1949 | Teddy系 |
| Marshua's Dancer | 1968 | Raise a Native系 |
| Marske | 1750 | Eclipse系 |
| Marsyas | 1940 | Son-in-Law系 |
| Martial | 1957 | Teddy系 |
| Masque | 1894 | Eclipse系 |
| Massine | 1920 | St. Simon系 |
| Master Kildare | 1875 | Pot 8 o's系 |
| Masthead | 1944 | Fairway系 |
| Match | 1958 | Teddy系 |
| Matchem | 1748 | Matchem系 |
| Matchmaker | 1892 | King Fergus系 | Matragon | 1887 | Bend Or系 |
| Matrice | 1951 | Fairway系 |
| McGee | 1900 | Pot 8 o's系 |
| Meadowlake | 1983 | Princequillo系 |
| Medaglia d'Oro | 1999 | Sadler's Wells系 |
| Meddler | 1890 | Pot 8 o's系 |
| Melbourne | 1834 | Matchem系 |
| Melton | 1882 | Pot 8 o's系 |
| Menow | 1935 | Pharamond系 |
| Mercury | 1778 | Eclipse系 |
| Merriwee | 1896 | St. Simon系 |
| Merry Hampton | 1884 | Hampton系 |
| (アラ) Mersuch | ---- | Arab父系 |
| Michelangelo | 1918 | Pot 8 o's系 |
| Midas | 1942 | Hyperion系 |
| Mid-Day Sun | 1934 | Hampton系 |
| Midstream | 1933 | Blandford系 |
| Migoli | 1944 | Bois Roussel系 |
| Milesian | 1953 | My Babu系 |
| Mill Reef | 1968 | Never Bend系 |
| Minamoto | 1964 | Relic系 |
| Mineshaft | 1999 | Bold Ruler系 |
| Minnesota Mac | 1964 | Himyar系 |
| Minting | 1883 | Pot 8 o's系 |
| Miracle | 1929 | Phalaris系 |
| Missel Thrush | 1897 | Bend Or系 |
| Miswaki | 1978 | Mr. Prospector系 |
| Mizzen Mast | 1998 | フォルティノ系 |
| Mochcz | 1909 | St. Simon系 |
| Mo Exception | 1981 | Owen Tudor系 |
| Monarque | 1852 | Pot 8 o's系 |
| Monteverdi | 1977 | Lyphard系 | Mortemer | 1868 | Herod系 |
| Moscow Ballet | 1982 | Nijinsky系 |
| Mossborough | 1947 | Nearco系 |
| Moss Trooper | 1972 | Djebel系 |
| Moulton | 1969 | Pharis系 |
| Mourne | 1954 | Brantome系 |
| Moutfleur | 1959 | Prince Rose系 |
| Mr. Prospector | 1970 | Raise a Native系 |
| Mr. Trouble | 1947 | Blenheim系 |
| Mt. Livermore | 1981 | Red God系 |
| Mujtahid | 1988 | Mr. Prospector系 |
| Muncaster | 1877 | Pot 8 o's系 |
| Music Boy | 1973 | Owen Tudor系 |
| Musket | 1867 | Pot 8 o's系 |
| My Babu | 1945 | Djebel系 |
| Myles Na Coppaleen | 1879 | Pot 8 o's系 |