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- Adelaide Cabete, physician and feminist (2009)
- Pedro Álvares Cabral, explorer (1945; 1969; 1992; 2000)
- Juan Rodríguez Cabrillo, explorer (1969; 1994)
- Luís da Câmara Pestana, bacteriologist (1966; 1999)
- Luís de Camões, poet (1898; 1911; 1924; 1972; 1980)
- Diogo Cão, explorer (1945; 1986; 1991)
- Bento de Jesus Caraça, mathematician (2001)
- Carlos I, king (1892–93; 1895–96; 1996)
- António Óscar Carmona, president (1934; 1945; 1970)
- Stuart Carvalhais, cartoonist (2005)
- Rómulo de Carvalho, poet (2006)
- Camilo Castelo Branco, writer (1925; 1990)
- Álvaro de Castro, politician (1980)
- João de Castro, viceroy of India (1994)
- Ana de Castro Osório, feminist writer (2009)
- João Chagas, journalist and politician (1979)
- Augusto Cid, cartoonist (2005)
- João Cid dos Santos (1907-1975), physician (1999)
- Eduardo Coelho (1935-1989, journalist (1964)
- Christopher Columbus, explorer (1992)
- José Correia da Serra, naturalist (1966)
- João Vaz Corte-Real, navigator (ship shown on stamp, 1966)
- Jaime Cortesão, historian and politician (1980)
- Pêro da Covilhã, diplomat and explorer (1988)
- Afonso Costa, politician (1979)
- António Augusto da Costa Mota, sculptor (1971)
- Padre Cruz, priest, blessed (1960)
- Álvaro Cunhal, politician (2005)
- Marie Curie, Polish physicist and chemist (1998)
Read more about this topic: List Of People On Stamps Of Portugal