This study was designed to determine whether the serum levels of 25-OH vitamin D influence the occurrence of infection with Helicobacter Pylori (H.Pylori) in patients on maintenance hemodialysis (HD). The study subjects were patients with end-stage renal disease who were undergoing maintenance dialysis at the hemodialysis section, Hajar Medical, Educational and Therapeutic Center, Shahrekord, Iran. The serum 25-OH vitamin D level and serum H. Pylori specific IgG antibody titers were measured using an enzyme-linked immunosorbent assay (ELISA) method. A total of 36 patients were studied including 21 males and 15 females. The mean age of the study group was 47 (+/- 17) years. The mean level of serum 25-OH vitamin D was 0.5 +/- 18.7 nmol/L (median: 3.5) while the mean value of serum H.Pylori specific IgG antibody titer was 7.7 (+/-9.9) u/ml (median: 2 u/ml). Thus, a significant positive correlation was found between the levels of serum 25-OH vitamin D and serum H. Pylori specific IgG antibody titers (data adjusted for age, urea reduction rate, duration and dose of dialysis) (r=0.36, p=0.043). Our study suggests that vitamin D may positively affect the chronic inflammatory status of dialysis patients and may potentiate the immune response in such patients. Because of this immuno-modulatory effect, vitamin D analogs may offer new means to control the inflammatory status in patients on maintenance dialysis.