Dumitru Posmagiu was born 1905 in Niculești, Buzău County, Romania to Dumitru Posmagiu (1865-1935) and Ana Cățoiu (c1875-c1940) and died 1925 of tuberculosis.
Siblings
| Name | Birth | Death | Joined with |
| Niculae Posmagiu (c1898-1918) | 1909 Niculești, Buzău County, Romania | 1918 | |
| Nelly Posmagiu (c1900-c1920) | 1900 Niculești, Buzău County, Romania | 1920 | |
| Dumitru Posmagiu (c1905-c1925) | 1905 Niculești, Buzău County, Romania | 1925 | |
| Lucreția Posmagiu (1909-2001) | 1909 Niculești, Buzău County, Romania | 2001 Hamburg, Germany | Ion Coșoreanu (1903-1976) |
| Emilia Posmagiu (c1910-c1985) | 1910 Niculești, Buzău County, Romania | 1985 Romania | Cincinat Bocioacă (c1905-c1970) |