Recent molecular epidemiological studies have shown that the inherited polymorphisms of VDR gene may be linked to prostate cancer risk and its aggressive phenotypes. However, the findings remain inconclusive. In this study, we investigated the association of the BsmI, ApaI and TaqI polymorphisms of VDR gene with prostate cancer risk in a Taiwanese population. In total, 160 prostate cancer patients and 205 age-matched male controls were studied between December 2000 and February 2003. No significant associations were found between the ApaI and TaqI polymorphisms and the risk of prostate cancer. However, the control group was found to have a significantly higher frequency of the BsmI 'BB' and 'Bb' genotypes (15.6%) than prostate cancer patients (8.1%). After adjustment for age, patients with BsmI 'BB' or 'Bb' genotypes were associated with a twofold decreased risk (OR = 0.50; 95% CI = 0.25-0.98; P = 0.045) for developing prostate cancer than those with 'bb' genotypes. This effect was particularly significant among men below the median age of 72 years (P = 0.017). Moreover, stronger associations were found in the advanced stages (T3/T4/N1/M1) and poorly differentiated disease (Gleason score >/= 7) ('BB' and 'Bb' vs 'bb': OR = 0.25; 95% CI = 0.07-0.83; P = 0.024 and OR = 0.25; 95% CI = 0.07-0.85; P = 0.026, respectively). Our findings suggest that the VDR BsmI polymorphism may play a significant role in the development of prostate cancer.