Thousands of Mauritanians lined the street from Nouakchott airport to welcome back president Mohamed Ould Abdel Aziz, who went to France for five weeks of medical treatment after being accidentally shot in a friendly fire incident.
His return puts an end to speculation over the state of his health, as well as over the future of Mauritania.
Analysts had warned that his extended departure could create the instability needed for another coup in the African nation which has suffered six since the 1970s.
Mr Aziz, a military general, came to power himself in a 2008 coup.
The 55-year-old leader waved to the crowd, and told reporters that he "at no point worried about a coup d'etat by the army," adding that he had "total confidence in the Mauritania military."