Marian Ciepielowski (30 August 1907–1 February 1973) was a Polish physician and scientist. A survivor of the Buchenwald concentration camp, he is best known for his activity as a saboteur within the camp's vaccine production unit. Ciepielowski's actions resulted in useful vaccines being distributed to camp inmates, while inactive and useless "vaccines" were sent to Nazi soldiers. After the war he emigrated to the United States.