Aim The majority of hemodialysis patients are hyperphosphate-mic. Hyperphosphatemia in these patients can lead to renal oste-odystrophy, vascular calcifcation, cardiovascular events, and is independently associated with mortality risk. The aim of this study was to evaluate the effect of intravenous vitamin C on phosphorus level in hemodialysis patients. Methods Using a double blind randomized clinical trial, a total of 60 qualified hemodialysis patients were randomly allocated in two intervention and control groups and serum phosphorus, CRP, calcium, albumin and PTH levels were measured. At the end of each hemodialysis session, intervention group received vitamin C vial (500mg/5cc) intravenously three times a week for 8 weeks and control group received normal saline in the same way. Data were collected before and after two months of treatment. Data were analyzed using independent t-test, paired t-test and chi-square test. Results Vitamin C treated group had a significant decrease in phosphorus (p=0.01), CRP level (p=0.01) and Ca�P product (p=0.03). In contrast, there was no significant difference in phosphorous (p= 0.5) and CRP levels (p= 0.6) and Ca�P product (p=0.7) in the control group. In addition, there was no statistically significant change in calcium (p=0.1), PTH (p=0.4) and albumin (p=0.4) levels in both groups. Conclusion Intravenous vitamin C can significantly decrease phosphorus level in hemodialysis patients