Two Americans -- James Rothman and Randy Schekman -- and Tomas Suedhof of Germany have won the 2013 Nobel Prize in Physiology or Medicine.
The prize was announced at the Swedish Academy in Stockholm on October 7.
It said the three researchers were awarded the prize for revealing how the cell organizes its transport system.
Rothman is a professor at Yale University; Schekman is a professor at the University of California at Berkeley; while Suedhof is a professor at Stanford University.
Medicine is the first of the Nobel prizes to be announced each year.
The most anticipated prize -- for peace -- will be announced on October 11 in Oslo.
Among the favorites for that award is the Pakistani teenage activist Malala Yousafzai, who was shot in the head by the Taliban last year for demanding education for girls.
The prizes -- worth 8 million Swedish crowns ($1.2 million) -- were established in the will of Swedish industrialist Alfred Nobel in 1895.
Based on reporting by AP and Reuters