Lieutenant Colonel (ret.) Tandja Mamadou, born in 1938) is a Nigerien politician who has been the sixth President of Niger since 1999, until he was deposed in February 2010. He was President of the National Movement of the Development Society (MNSD) from 1991 to 1999 and unsuccessfully ran as the MNSD’s presidential candidate in 1993 and 1996 before being elected to his first term in 1999. While serving as President of Niger, he was also Chairman of the Economic Community of West African States from 2005 to 2007.

n 1991, Tandja emerged as the head of one of two powerful factions in the ruling National Movement of the Development Society (Mouvement National pour la Societé de Développement, MNSD), and at a party congress held in November 1991, he was elected as MNSD President. Tandja’s obtaining of the party leadership over rival faction leader Moumouni Adamou Djermakoye marked a departure from the traditional dominance of the party by Djermakoye’s Zarma (Djerma) ethnic group.

On 18th February 2010, during a government meeting at the presidential palace, rebel soldiers attacked and deposed Tandja in a coup d’état, establishing a military junta called the Supreme Council for the Restoration of Democracy (CSRD). Tandja is believed to be held at a military barracks on the outskirts of Niamey.