To derive a precise estimation of the associations between the cytochrome P450 1B1 (CYP1B1) 4326C/G variants and prostate cancer (PCa) risk or aggressiveness, a meta-analysis was performed using all eligible published studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the association in seven literature studies with 2788 cases and 2968 controls. In the overall analysis, no significant association was found between the CYP1B1 4326C/G polymorphism and PCa risk, but ethnicity subgroup analyses and a case-source analysis revealed significant associations. The 4326G allele showed a significant association with increased PCa risk in Asians (OR=1.52, 95% CI: 1.20-1.92), and significant associations were also observed in a heterozygote comparison (OR=1.40, 95% CI: 1.03-1.89), a homozygote comparison (OR=2.38, 95% CI: 1.31-4.33) and in a dominant genetic model (OR=1.52, 95% CI: 1.14-2.01). Moreover, the 4326G allele was also significantly correlated with an increased risk of sporadic PCa (OR=1.13, 95% CI: 1.04-1.24), and significant associations were observed in a heterozygote comparison (OR=1.16, 95% CI: 1.02-1.33), a homozygote comparison (OR=1.24, 95% CI: 1.03-1.49) and a dominant genetic model (OR=1.19, 95% CI: 1.05-1.34). The overall analyses and all subgroup analyses showed no significant association between the 4326C/G polymorphism and PCa aggressiveness. Our meta-analysis showed that CYP1B1 4326G allele is significantly associated with an increased PCa risk in Asians and in sporadic PCa cases.