| Inscription | Country | Years | #Issued |
| Macau | Macao | 1884- | 550 |
| Madagascar | Madagascar | 1891-1957 | 300 |
| Madeira | Portugal: Madeira(aut/isl) | 1868-1928 | 75 |
| Madrid | Spain: Madrid (cty) | 1920 | 13 |
| Magyar Kir. Posta | Hungary | 1874-1944 | 600 |
| Magyarorszag | Hungary | 1925-36,1991- | 140 |
| Magyar Posta | Hungary | 1945-91 | 3200 |
| Magyar Tanacs Koztarsasag | Hungary | 1919 | 30 |
| Mahra State | Yemen: Mahra State(exploitative) | <1967? | 200? |
| Malacca | Malaya: Malacca(sta) | 1948- | 100 |
| Malawi | Malawi | 1964- | 550 |
| Malaya | Malaya | 1957-63 | 40 |
| Malaysia | Malaysia | 1964- | 400 |
| Maldive Islands | Maldive Islands(isl) | 1950-69 | 270 |
| Maldives | Maldive Islands(isl) | 1909-33 | 20 |
| Malta | Malta | 1860- | 800 |
| Manama | Manama(exploitative/cty) | 1968-72? | 900 |
| Marianen | Mariana Islands(isl) | 1900-19 | 30 |
| Maroc | French Morocco | ||
| Maroc | Morocco | 1956-58 | 25 |
| Marruecos | Morocco (Northern) | 1956-57 | 30 |
| Marruecos | Spanish Morocco | 1903-55 | 400 |
| Marshall-Inseln | Marshall Islands | 1901-16 | 15 |
| Martinique | France: Martinique(aut/isl) | 1886-1947 | 260 |
| Mauritanie | Mauritania | 1906-1941 | 150 |
| Mauritius | Mauritius | 1847- | 700 |
| Mayotte | Mayotte | 1892-1912 | 32 |
| Mayotte et Nossi-Be | Madagascar (unissued) | 1943 | |
| Mbretnia Shqyptare | Albania (air) | 1930-31 | 20 |
| Mbretnija Shqiptare | Albania | 1939-45 | 70 |
| Mecklenburg Schwerin | Germany: Mecklenburg-Schwerin(sta) | 1856-67 | 15 |
| Mecklenburg Strelitz | Germany: Mecklenburg-Strelitz(sta) | 1864 | 8 |
| M.E.F. | Middle East Forces-Italian colonies (British occ) | 1942 | |
| Melaka | Malaya: Malacca(sta) | ||
| Memel | Memel | 1920-23 | 200 |
| Mesopotamia | Turkey (adm) or Iraq or (french occ)? | ||
| Mexico | Mexico | 1856- | 2200 |
| Micronesia | Federated States of Micronesia | ||
| Militarpost Eilmarke | Bosnia (militar) | 1916 | 4 |
| Militarpost Portomarke | Bosnia (Postage Due) | 1916-18 | 13 |
| Mocambique | Mozambique | 1877- | 950 |
| Moheli | Moheli | 1906-12 | 25 |
| Moldova | Moldova | 1991- | |
| Monaco | Monaco | 1939- | 1700 |
| Mongolia | Mongolia | 1926- | 1600 |
| Montenegro (ovpt) | Montenegro (German occ) | 1917-41 | 25 |
| Montevideo | Uruguay: Montevideo(cty) | 1858-60 | 10 |
| Montserrat | Montserrat | 1876- | 600 |
| Morvi State | India: Morvi(sta) | 1931-48 | 20 |
| Moyen Congo | Middle Congo | 1907-33 | 120 |
| Muscat & Oman | Oman | 1966-70 | 30 |
| Mutawakelite Kingdom of Yemen | Yemen | 1951-57 | 30 |
| Mutawakelite Kingdom of Yemen | Yemen (rebelion) | 1968-73 | 1000 |
| My Bonnie | Bogus |
If there are any missing inscription, tell me : marcosampaio@mail.telepac.pt
