At this time, it is unclear what Prince Philip had been suffering with, but he has recovered enough to be released from the hospital.
Philip was admitted Wednesday, the palace said, for the treatment of an infection related to a pre-existing condition.
The details of the current state of health 96-year-old Duke at Buckingham Palace refused to discuss.
Britain's Prince Philip was discharged Thursday from a hospital after he was treated for an infection, Buckingham Palace said.
News of the illness came shortly after Philip had announced he would stand down from official public duties from autumn this year, weeks before his 96th birthday earlier this month.
Philip - due to step down from public life later this year - has suffered bladder infections in the past. "Her Majesty is being kept informed and will attend Royal Ascot as planned this afternoon", it added.
The Duke is an advocate of healthy eating combined with exercise and is well-known for his robust constitution.