Objectives: To investigate the association between a cytochrome P450 17α-hydroxylase gene (CYP17) polymorphism and survival in Caucasian patients with androgen-independent prostate cancer (AIPC). Methods: The study used 222 samples acquired from Caucasian patients with AIPC. The CYP17 polymorphism (-34T>C) was analyzed using polymerase chain reaction amplification followed by restriction fragment length polymorphism detection. Results: No significant differences were observed in the frequencies of the CYP17 genotype in relation to categorized Gleason scores, age at diagnosis, or hormone therapy. The median survival was significantly longer in 126 patients with the CYP17 A2 allele (8.9 years) genotype than in 96 patients with the A1 allele (6.7 years) genotype (P = 0.040 by log-rank test). Similarly, the estimated survival probability at 10 years (24% in A1 allele versus 43% in A2 allele) showed a statistically significant difference between the two groups (P = 0.002 by the permutation test). Conclusions: These results suggest that the CYP17 polymorphism is associated with overall survival in patients with AIPC.