Boris Yeltsin, who was admitted to hospital more than a month ago, had fallen ill with pneumonia but has fully recovered.
The director of the Russian presidential administration's medical centre says Mr Yeltsin had a tough time overcoming the flu, which landed him in the hospital on January 30.
The illness was complicated by a form of pneumonia, and the former Russian president was treated with antibiotics, Sergei Mironov added.
He says Mr Yeltsin's condition is "fully satisfactory, the inflammation of the lungs has been cured in full".
Mr Mironov says Mr Yeltsin might be released from the hospital within days.