Serum ferritin as well as blood mercury are reported to be associated with chronic inflammation. However, the relation between serum ferritin and blood mercury has not yet been established. We utilized the Korea National Health and Nutrition Examination Survey (KNHANES, 2008-2012) 10,977 subjects (5433 males and 5544 females). To evaluate the association of serum ferritin and blood mercury cross-sectionally, complex sample analysis was conducted after adjustment for the relevant variables. Serum concentrations of ferritin and blood mercury were higher in males than in females (115.7 ± 1.7 vs. 40.9 ± 0.7 ng/mL and 5.0 ± 0.1 vs. 3.6 ± 0.1 μg/L, respectively). Serum ferritin and blood mercury concentrations had significant correlations in both genders after adjustment (r = 0.062, P < 0.001 in males; r = 0.055, P < 0.001 in females). The analysis of covariance (ANCOVA) test showed significantly higher serum ferritin according to the tertile of blood mercury (P = 0.007) in males. The adjusted odds ratio of having the highest tertile of serum ferritin in the top tertile of blood mercury in males was 1.52 (95 % confidence interval (CI), 1.05-2.21). Thus, the current study indicates that blood mercury concentration can be a factor for the elevated serum ferritin concentration.