After five appearances for the club, Doriva was given a one-year contract with Middlesbrough on 21 July 2003. In his first full season at the club, Doriva was first choice in midfield alongside George Boateng. He found his chances limited after this, however, due to the emergence of Stewart Downing and the conversion of Boudewijn Zenden to central midfield. On 11 February 2004, in a 3–2 win over Manchester United at Old Trafford, Doriva was pushed by Paul Scholes, who in April was given a three-match ban for the incident. On 29 February he started as Middlesbrough won their first major trophy, the 2004 Football League Cup Final, with a 2–1 win over Bolton Wanderers in the Millennium Stadium in Cardiff. His only goal for Middlesbrough came in a 2–1 victory at Notts County in the third round of the FA Cup on 8 January 2005.