The 92-year-old husband of Queen Elizabeth II smiled as he walked out of the clinic. He was there for exploratory surgery on his abdomen. Philip has suffered heart and bladder problems in the past.
Buckingham Palace said Philip was "in good condition and good spirits." No other details were released about his condition, but royal officials say he is making satisfactory progress.
The prince is expected to spend two months recovering at Windsor Castle near London.
The Associated Press contributed to this report.