Li-Fraumeni Syndrome (LFS) is an autosomal dominant genetic disorder associated with mutations in the TP53 gene and characterized by a propensity to develop a variety of malignancies resulting in a shortened lifespan. We report a case of prostate cancer in a 50 year old male with LFS. Experimental studies suggest that TP53 mutations in prostate cancer are associated with therapeutic resistance to radiation, chemotherapy, and anti-androgens, implying that LFS men may experience more aggressive cancer biology with implications for therapeutic decisions. The potential of prostate cancer to develop earlier in LFS favors institution of screening at earlier ages.