Blueberries are amongst the most commonly consumed berries in the United States. Berries in general are rich in phenolic compounds, which are known for their high antioxidant capacity. Specifically, evidence from in vitro, in vivo and a few clinical studies suggest that blueberries and their active constituents show promise as effective anti-cancer agents, both in the form of functional foods and as nutritional supplements. Some of the mechanisms by which blueberries have been shown to prevent carcinogenesis include inhibition of the production of pro-inflammatory molecules, oxidative stress and products of oxidative stress such as DNA damage, inhibition of cancer cell proliferation and increased apoptosis. This review will focus on the preclinical and clinical evidence that supports blueberries as an anti-cancer fruit, as well as expressing the need for more preclinical studies and the conduction of clinical studies with respect to the cancer preventive ability of blueberries.