Patients on hemodialysis are a high-risk group for human T-lymphotropic virus 1 (HTLV1) infection and other viruses transmitted by blood or blood products. The Razavi and South Khorasan provinces in Iran are the endemic areas for this virus. This study compares proviral load of HTLV1 in patients on hemodialysis with otherwise healthy carriers of HTLV1.In this case-control study the proviral load of the HTLV1 virus was compared between 25 patients on long-term hemodialysis who were positive for HTLV1 and 25 healthy carriers of HTLV1, to determine The effect of uremia and chronic hemodialysis on the proviral load. virus proviral load was determined using a real-time polymerase chain reaction method.There was a significant difference in the proviral load between the hemodialysis patients and the control group (903 +/- 182 copies per mL versus 117 +/- 186 copies per mL, respectively; P = .008). No significant correlation was found between the proviral load and haematocrit or serum levels of urea, creatinine, parathyroid hormone, calcium , and phosphorus level in hemodialysis patients, but proviral load of HTLV1 was significantly correlated with leukocyte count (r = -0.46, P = .02), hemodialysis duration (r = 0.48, P = .02), and the numbers of blood transfusions (r = 0.71, P < .01). Conclusions. The immune deficiency related to end-stage renal disease and uremia is the probable cause of significantly higher HTLV1 proviral load in hemodialysis patients compared to healthy HTLV1 carriers. This high HTLV1 proviral load might be due to immune dysfunction in chronic hemodialysis patients.