Walter Christian Ploeser (January 7, 1907 – November 17, 1993) was a U.S. Representative from Missouri and United States Ambassador to Paraguay and Costa Rica. Born in St. Louis, Missouri, Ploeser attended the public schools of St. Louis, Missouri, Casper and Lusk, Wyoming, and the City College of Law and Finance, St. Louis, Missouri.He engaged in the insurance business in St. Louis, Missouri, in 1922 and founded his own company in 1933.Organizer and chairman of the board of Marine Underwriters Corp. 1935.He served in the State house of representatives in 1931 and 1932.