Sitting in a wheelchair and dressed in a blue three-piece suit and red tie, Bouteflika placed his right hand on the Koran as he repeated in a frail voice the oath read out by Supreme Court chief Slimane Boudi.
The 77-year-old then issued a brief statement in which he said his election was a "victory for the state".
At the start of the ceremony, Bouteflika had placed his hands on his knees as he inspected soldiers following a display of their weapons outside the beachfront Palace of Nations resort.
Bouteflika, who was also in a wheelchair when he cast his own ballot on election day, has hardly been seen in public since a mini-stroke which confined him to hospital in Paris for three months last year.
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Official results showed he won 81.5 per cent of the votes in an election marred by low turnout and claims of fraud by his opponents, including main rival Ali Benflis, who received just 12.18 per cent.
The opposition had said they would boycott today's swearing in ceremony, including five parties that had called on their supporters to stay away from the election.