Americans James E. Rothman and Randy W. Schekman and German Thomas C. Sudhof were awarded the prize Monday for discoveries of how the body's cells decide when and where to deliver the molecules they produce.
Disruptions of this delivery system contribute to diabetes, neurological diseases and immunological disorders.
In the coming days, prize committees will announce the laureates in chemistry, literature, peace and economics.
Swedish industrialist Alfred Nobel created the prizes in 1895 to honor work in physics, chemistry, literature and peace. The first economics prize was awarded in 1969.