Mamadou Niang is a Senegalese footballer who plays as a forward for Qatar club Al Sadd in the Qatar National First Division. He has represented Senegal at international level, participating in the 2004, 2006, and 2008 African Cup of Nations. He wears the number 7 jersey. He is the older brother of Papa Niang, who currently plays at FF Jaro in Finnish Veikkausliiga.
After beginning his career with the Le Havre youth team, Niang turned professional at 18 years of age with Troyes. He had a mixed beginning to his career with his first season featuring ten Ligue 1 starts, all from the bench, the following season would show little improvement with 17 starts and only 3 league goals.
A loan period with second division Metz allowed him to hone his skills, contributing 5 goals in 12 appearances and helping Metz return to top flight French football for the 2003–04 season.
Jean Fernandez, the Metz manager, tried to make the loan deal into a permanent move but failed and Niang left Troyes for Strasbourg. The arrival of Danijel Ljuboja, to Strasbourg at the same time allowed Niang to form an important strike partnership until Ljuboja moved to Paris Saint-Germain. Niang didn't score again for the remainder of the second half of that season.
The 2004–05 season saw Mickaël Pagis arrive at Strasbourg, and a fruitful new partnership was formed, with the pair linking up for 27 goals in the league. This partnership helped Strasbourg make it to the Coupe de la Ligue final, where victory over Caen gave Strasbourg their second Coupe de la Ligue trophy.
Mamadou niang training with Marseille
In 2005, Niang moved to Marseille for a reported fee of €7 million. He was joined six months later by Mickaël Pagis. Niang finished the season as Marseille's top scorer with ten goals but Marseille lost the Coupe de France final to Paris Saint-Germain.
Niang would go on to finish the 2009–10 season with 18 goals in Ligue 1, making him the highest scorer in the league and Marseille's highest scorer with 28 goals in all competitions.
Niang was selected OM player of the month for May 2008.
He signed a 3+1 year deal with Fenerbahçe on 14 August 2010 for a fee of reported €8 million. Mamadou Niang had made a great start with Fenerbahçe SK when he scored 7 goals in his first 6 league appearances. Niang scored his first hat-trick for Fenerbahçe on his 5th appearance when they won 6-2 against Kasımpaşa. Niang helped his side win the 2010–11 Süper Lig, scoring 16 goals in 29 appearances.
On 6 September 2011 he was sold to Al-Sadd for €7.5 million.
On 19 October 2011, at the 2011 AFC Champions League Semi-final match against Suwon Samsung Bluewings, he scored a controversial second goal for his team, not returning the ball to the opponent team which had kicked the ball out deliberately due to an injury situation. While Suwon players were standing off-guard expecting to have possession back, Niang ran straight to the opponent's side and found the net easily. The goal induced an intrusion of a home fan and a huge melee of both players and bench. He then got himself sent-off in injury time for kicking the ball away when he was flagged offside, receiving another yellow card in addition to his previous, meaning he could not participate in the second leg in Doha.