Prostate cancer is a complex, multifactorial disease with genetic and environmental factors involved in its etiology. The search for genetic determinants involved in the disease has proven to be challenging, in part because such complex diseases are often not amenable to characterization by linkage analysis and positional cloning as is the case for diseases with simple Mendelian genetic inheritance. Prostate cancer susceptibility loci that have been reported so far include HPC1 (1q24-q25), PCAP (1q42-q43), HPCX (Xq27-q28), CAPB (1p36), HPC20 (20q13), HPC2/ELAC2 (17p11) and 16q23. Prostate cancer aggressiveness loci have also been reported (5q31-q33, 7q32 and 19q12). Further complicating the process is the existence of polymorphisms in several genes associated with prostate cancer including, AR, PSA, SRD5A2, VDR and CYP isoforms. These polymorphisms, however, are not thought to be highly penetrant alleles in families at high risk for prostate cancer. It is clear that prostate cancer etiology involves several genetic loci with no major gene accounting for a large proportion of susceptibility to the disease.