1944 United States Senate election in Washington

The 1944 United States Senate election in Washington was held on November 7, 1944. Incumbent Democratic U.S. Senator Homer Bone resigned in April, having been appointed and confirmed to the United States Court of Appeals for the Ninth Circuit in April. Democratic U.S. Representative Warren Magnuson won the open race over Republican Harry Cain, the mayor of Tacoma and was appointed to the vacant seat.

Blanket primary
The blanket primary was held on July 11, 1944.

Democratic

 * John A. Hogg
 * Warren G. Magnuson, U.S. Representative from Seattle since 1937
 * Martin F. Smith, former U.S. Representative from Hoquiam (1933–1943)

Republican

 * Stella Alene Blanchard, candidate for U.S. House from Goldendale in 1942
 * Harry P. Cain, Mayor of Tacoma since 1940
 * Gordon B. Dodd
 * J. Parkhurst Douglas
 * Howard E. Foster, candidate for U.S. Senate in 1938 and 1940
 * Joseph A. Mallery, Justice of the Washington Supreme Court
 * Charles Arlin Nave
 * Clement L. Niswonger
 * Edwin L. Rice
 * Cameron Sherwood, candidate for U.S. House from Walla Walla in 1942
 * Herb Sieler, nominee for U.S. House from Chehalis in 1936

Candidates

 * Harry P. Cain, Mayor of Tacoma (Republican)
 * Warren Magnuson, U.S. Representative from Seattle (Democratic)
 * Ray C. Roberts (Socialist)
 * Josephine B. Sulston (Prohibition)

Results
After the election, Governor Arthur B. Langlie appointed Magnuson to the vacant seat left by Bone's resignation, and he took office on December 14.

Cain would win election to Washington's other Senate seat in 1946 and served alongside Magnuson from 1947 to 1953.