Diogo Pereira Mateus (born Lisbon, February 7, 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.