Financial terms were not disclosed.
Robinson -- who managed the team when it was in Montreal -- will return for his fifth season at the helm. He has guided the Nationals to 314-334 record -- including an 81-81 record this year, the team's first in Washington.
Robinson -- the first black manager in Major League Baseball -- has a lifetime managing record of 994-1,085 in 15 seasons. He ranks sixth among active managers for most victories, and was named Manager of the Year in 1989 with Baltimore.