Philip, who turns 91 Saturday, was taken by ambulance from Windsor Castle to King Edward VII Hospital in London. He is expected to remain there for several days.
"His royal highness the duke of Edinburgh was taken to King Edward VII Hospital in London this afternoon from Windsor Castle as a precautionary measure after developing a bladder infection, which is being assessed and treated," the palace said in a statement. "Prince Philip will remain in hospital under observation for a few days. He is understandably disappointed about missing this evening's Diamond Jubilee concert and tomorrow's engagements."
The Daily Telegraph reported there was likely to be speculation the prince's health suffered Sunday while enduring bitter cold and rain during a boat pageant on the Thames to celebrate his wife's 60th year on the British throne.