Sleep, like eating and breathing, is an essential part of the daily life cycle. Although the science is still emerging, sleep plays an important role in immune, cardiovascular, and neurocognitive function. Despite its great importance, nearly 40% of U.S. adults experience problems with sleep ranging from insufficient total sleep time, trouble initiating or maintaining sleep (Insomnia), circadian rhythm disorders, sleep-related movement disorders, and sleep-related breathing disorders such as obstructive sleep apnea (OSA). Herein, we discuss new evidence that suggests that sleep may also affect carcinogenesis. Specifically, we review recent epidemiologic data suggesting links between cancer and OSA. As OSA is a common, underdiagnosed, and undertreated condition, this has public health implications. Intriguing animal model data support a link between cancer and sleep/OSA, although mechanisms are not yet clear. Leaders in the fields of sleep medicine, pulmonology, and oncology recently met to review and discuss these data, as well as to outline future directions of study. We propose a multidisciplinary, three-pronged approach to studying the associations between cancer and sleep, utilizing mutually interactive epidemiologic studies, preclinical models, and early-phase clinical trials. Cancer Prev Res; 9(11); 821-7. ©2016 AACR.