In the first stage of the study, 112 hemodialysis patients and 23 healthy control subjects were qualified. During this oneyear study period, observed were significant low concentrations of vitamin C in the hemodialysis patient group in comparison to the control group. During HD, serum concentration of vitamin C decreased about 45 %. During the second stage of the study, 68 hemodialysis patients were qualified for vitamin C supplementation. After the supplementation period, vitamin C concentration levels significantly increased statistically, returning to similar baseline values during the next 2 months. Statistically significant negative correlation was observed between the increase in vitamin C concentration and the degree of creatinine removal during hemodialysis (et/co). Non-parametric tests showed statistically significant increase (p< 0,00001) of hemoglobin concentration and hematocrit value and statistically significant differences (p<0,00001) in erythropoietin doses during the supplementation cycle, 2 and 4 months after its termination. Dosage of rHuEPO decreased from 3000 U/week/patient to 2000 U/week/patient after the vitamin C supplementation cycle, 2 and 4 months after its termination.