The Nobel Assembly at Karolinska Institute announced that the three recipients were recognized "for their discoveries of how cells sense and adapt to oxygen availability", Efe news reported.
With their work they were able to understand how oxygen levels affect cell metabolism and physiological function.
Their discoveries could pave the way in the development of new strategies to fight anemia, cancer and other diseases, according to the institute.
Kaelin, born in New York in 1957, is a specialist in internal medicine and oncology.
Semenza, born in 1955 and also a New Yorker, is a paediatrician.
And Ratcliffe was born in Lancashire in 1954, and is an expert in nephrology, a medicine specialising in kidneys.
The announcement in Medicine kicks off this year's prestigious awards, which will be followed in the coming days by prizes in Physics, Chemistry, Literature, Peace and Economics.
This edition will see two prizes in Literature being announced as an exception, as last year's were postponed owing to allegations of sexual abuse within the Swedish Academy.
The awards will be presented on December 10, the anniversary of the death of its founder Alfred Nobel, in a double ceremony at the Konserthus in Stockholm and Oslo City Hall, for the Peace Prize.
All prizes include a cash prize, which this year amounts to 9 million Swedish kronor ($912,000).
( With inputs from IANS )