On 27 May 2008, he signed a five-year contract with Shakhtar Donetsk. The Ukrainian club agreed to pay €9 million for the player. On 29 May 2009, unable to establish himself in Donetsk, Martins joined German club Werder Bremen on loan. Bremen had initially attempted to sign Martins the previous summer, but the player opted for Shakhtar. On 29 January 2010, Bremen terminated his contract and he returned to Shakhtar Donetsk. At 16:44 on the final day of the transfer window, a six-month loan deal between Shakhtar and Wigan was agreed to take the player to the Premier League. He signed for Wigan Athletic on 1 February on loan. After returning to Shakhtar as a reserve, Martins was negotiated with Grêmio Foot-Ball Porto Alegrense and signed with the Brazilian team for a five-year contract starting in 2012.
Born in Bolivia to a Brazilian father (Mauro Martins, former footballer) and Bolivian mother, Marcelo Martins has played for the Brazilian U18 national team at the youth level, becoming the first foreign player to be part of it and the fifth foreign player to wear the Brazilian National Team's shirt in an official match, but chose to play for the Bolivian senior national team as a professional.
Due to his success playing for Cruzeiro, he received his first call-up for a friendly match against Peru on 12 September 2007. Martins scored his first international goal on 20 November 2007, during a 2010 World Cup qualifier against Venezuela. He was also one of the goalscorers in Bolivia's 6–1 victory over Diego Maradona's Argentina on 1 April 2009. On 26 March 2013, he scored a goal in the 1-1 draw against Argentina.
^Hispanic name: A person's name consists of a given name (simple or composite) followed by two family names, traditionally the first is father's family surname (paternal) and the second one is mother's family surname (maternal).
^Brazilian name: A typical lusophone name is composed of one or two given names and two family names. The first surname is usually the mother's family surname and the second surname is the father's family surname; however, the order of the surnames can be reversed and traditionally people is known just by the second surname (paternal), having the first surname used in legal and formal expressions.