It has been suggested that hOGG1 Ser326Cys polymorphism may be a risk factor for colorectal cancer. Published data on its association with colorectal cancer generated contradictory results; thus, we performed an updated meta-analysis of eligible published studies to estimate the effect of hOGG1 Ser326Cys polymorphism on colorectal cancer susceptibility. We reviewed many abstracts and finally included 18 eligible case-control studies comprising 5235 cases and 8438 controls. We pooled data with a fixed or random-effect model. Subgroup analysis by ethnicity was also performed. The overall data indicated a significant association of hOGG1 Ser326Cys polymorphism on colorectal cancer risk (allele model OR = 1.14, 95 %CI 1.02-1.27; homozygote model OR = 1.32, 95 %CI 0.92-1.92; recessive model OR = 1.12, 95 %CI 1.00-1.26; dominant model OR = 1.15, 95 %CI 1.00-1.32). Furthermore, in the subgroup analysis by ethnicity, increased cancer risk was observed among Caucasians under the allele, heterogeneity, recessive, and dominant models (allele model OR = 1.23, 95 %CI = 1.05-1.44; homozygote model OR = 1.49, 95%CI 1.05-2.12; recessive model OR = 1.40, 95 %CI 1.16-1.69; dominant model OR = 1.21, 95 %CI = 1.12-1.45). In summary, the present meta-analysis suggested that hOGG1 Ser326Cys polymorphism might modify the susceptibility to colorectal cancer among the total population, especially among Caucasians.