| Birth Date: | 7 February 1980 |
| Birth Place: | Lisboa, Portugal |
| Weight: | 205lbs |
| Ru Currentposition: | centre |
| Ru Position: | Centre |
| Years1: | 2006 |
| Clubs1: | Munster |
| Apps1: | 1 |
| Points1: | 0 |
| Repyears1: | 2000–2010 |
| Repcaps1: | 75 |
| Reppoints1: | 78 |
| Ru Sevensnationalyears1: | 2014–2015 |
| Ru Sevensnationalteam1: | Portugal |
| Ru Sevensnationalcomp1: | 8 |
| Relatives: | David Mateus (twin) |
Diogo Pereira Mateus (born Lisbon, 7 February 1980) is a Portuguese rugby union player. He played as a centre.
He came through the ranks at Belenenses (after a stint at "Clube dos TLP"), he was on the books with Heineken Cup champions Munster in the 2006/07 season. He is 1.75 m tall and weighs 93 kg. He has a twin brother David Mateus, who was also a rugby player.
He had 75 caps for Portugal, from 2000 to 2010, scoring 15 tries and 1 penalty, 78 points on aggregate. He was called for the 2007 Rugby World Cup, playing in three games and remaining scoreless.[1]
He was also a notable 7's player, being captain of the Portuguese national Sevens rugby team.