Phytochemicals are widely noted for their role in chemoprevention. Potato (Solanum tuberosum L.) is the third most important food crop worldwide and is considered a significant source of antioxidants, providing an ideal delivery system for beneficial compounds. The anti-proliferative and pro-apoptotic properties of potato bioactive compounds have been reported in vitro on human prostate cancer cell lines. However, in vivo studies are limited, and more information is needed to determine the chemopreventive properties of potato in the diet. The objective of this study was to evaluate the effects of potato bioactives on prostate cancer in vivo using a mouse model. Athymic nude mice received xenografts of human prostate cancer cells (PC-3) and were administered extracts of potato bioactives from either the white flesh Solanum bulbocastanum (PI243510) or CO112F2-2P/P (purple-flesh Colorado selection), while control mice received water. Neither potato extract provided a significant reduction in tumor growth nor reduced levels of the pro-angiogenic protein VEGF, but the S. bulbocastanum extract reduced expression of metastasis associated protein 1 (MTA1) in tumors, and both potato extracts reduced MTA1 expression in lungs, suggesting the need for further research on the potential chemopreventive or chemotherapeutic properties of potato bioactives.