One of the common problems in patients on hemodialysis (HD) is marital dissatisfaction. Because anemia and fatigue are two important factors for marital dissatisfaction, and vitamin C can ameliorate both of them, we carried out this study to evaluate the effect of vitamin C on marital satisfaction among HD patients. This randomized, placebo-controlled, double-blind and parallel-group trial was conducted on 62 HD patients. The MFI-20 and ENRICH questionnaires were completed at the start and end of study. Required laboratory parameters including serum levels of hemoglobin (Hb), hematocrit (Hct) and ferritin were also measured at the start and at the end of the study. In the intervention group, 250 mg of vitamin C was injected intravenously immediately at the end of each HD session three times a week for eight consequent weeks. In the control group, placebo saline was injected. There was a significant change in the level of fatigue (P = 0.01) and the serum levels of Hb (P = 0.006) and Hct (P = 0.02). The mean of the marital satisfaction score increased significantly in the intervention group (P = 0.001): Baseline score of 35.7 ± 5.10 versus a final score of 38.0 ± 5.30. However, the mean of marital satisfaction score decreased in the control group: Baseline 37.1 ± 7.10 versus a final score of 34.7 ± 7.40. Our findings suggest that vitamin C supplementation can modify the marital satisfaction. Further studies are recommended.