Karl Eugen Hammerstedt (19 May 1903 - 28 December 1960) was a Norwegian politician for the Communist Party.
He was elected to the Norwegian Parliament from the Market towns of Telemark and Aust-Agder counties in 1945, but was not re-elected in 1949 as the Communist Party dropped from 11 to 0 seats in Parliament.
Markussen was born in Porsgrunn and was a member of the Porsgrunn city council during the terms 1934 - 1937 and 1937 - 1940.