This study was conducted to evaluate the relationship between exposure to mercury and color vision loss in populations located within fishery areas in South Korea. From a total of 511 subjects, 401 were assessed for acquired color vision loss. Subjects determined to have congenital loss or subjects with visual acuity less than 0.6 were excluded from the study. Mercury concentrations were analyzed in blood, urine, and hair samples. The Ishihara test was used to assess congenital color vision loss, and the Lanthony test was used for acquired color vision loss. Acquired color vision loss was present in 56 (14%) of the subjects and 345 (86%) subjects were normal. The geometric means of mercury concentration were 3.78 ${mu}g/L$ in blood, 0.64 ${mu}g/g$ creatinine in urine, and 1.16 ${mu}g/g$ in hair. Although mercury was identified in relatively low concentrations, mercury concentrations in subjects with acquired color vision loss were higher than that of normal subjects. The frequency of color vision loss in subjects with higher mercury concentrations was increased compared to subjects with lower mercury concentrations. The color confusion index increased with increasing mercury levels. This study suggests that exposure to low levels of mercury affects color vision loss as an early marker of neurotoxic damage in humans.