Among numerous Luiseño Indians of San Diego County, California, cancer is considered to be any tumor or growth that is possibly life threatening. A medical anthropology research project reveals that current and former Luiseño cancer patients share illness causation theories distinct from those of their kin. The patients believe their bouts with cancer stem from genetic predilection and/or God?s will. In contrast, other Luiseño band members who do not have cancer assert that almost all cancer is caused by either (1) chemical pollutants in the air, water, and food; or (2) prior biomedical treatments that have gone awry. Imbalances of both natural and bodily elements are generally traced to particular culprits. This paper will detail these variances of Luiseño cancer etiologies and their impact on prevention policies.