The International Congress of Mathematicians at Zurich in 1932 adopted his proposal, and the Fields Medal was first awarded at the next congress, held at Oslo in 1936. Fields Medals were not awarded during World War II so the second Fields Medals were not awarded until 1950.
Fields wished that the awards should recognize both existing mathematical work and also the promise of future achievement. To fit with these wishes Fields Medals may only be awarded to mathematicans under the age of 40.
In 2010 medals were awarded to:
Elon Lindenstrauss
Ngô Báo Châu
Stanislav Smirnov
Cédric Villani
Earlier winners of the medals are given below.
1936 L V Ahlfors 1936 J Douglas 1950 L Schwartz 1950 A Selberg 1954 K Kodaira 1954 JP Serre 1958 K F Roth 1958 R Thom 1962 L V Hörmander 1962 J W Milnor 1966 M F Atiyah 1966 P J Cohen 1966 A Grothendieck 1966 S Smale 1970 A Baker 1970 H Hironaka 1970 S P Novikov 1970 J G Thompson  1974 E Bombieri 1974 D B Mumford 1978 P R Deligne 1978 C L Fefferman 1978 G A Margulis 1978 D G Quillen 1982 A Connes 1982 W P Thurston 1982 ST Yau 1986 S Donaldson 1986 G Faltings 1986 M Freedman 1990 V Drinfeld 1990 V Jones 1990 S Mori 1990 E Witten 1994 PL Lions 1994 JC Yoccoz  1994 J Bourgain 1994 E Zelmanov 1998 R Borcherds 1998 T Gowers 1998 Maxim Kontsevich 1998 C McMullen 2002 L Lafforgue 2002 V Voevodsky 2006 A Okounkov 2006 G Perelman (who declined it) 2006 T Tao 2006 W Werner

Other Web sites:
More details of the Fields medals are available at the IMU website
The URL of this page is:
http://wwwhistory.mcs.standrews.ac.uk/history/Societies/FieldsMedal.html