Lloyd John Old (September 23, 1933 – November 28, 2011) was one of the founders and standard-bearers of the field of cancer immunology. When Old began his career in 1958, tumor immunology was in its infancy. Today, cancer immunotherapies are emerging as a significant advance in cancer therapy. Old died November 28, 2011, in his New York City home, after several years battling advanced prostate cancer.