Background: Helicobacter pylori has been identified as a possible cause of vitamin B<sub>12</sub> deficiency in the general population. We assessed any potential relationship between low cyanocobalamin serum levels and Helicobacter pylori status in hemodialysis patients and subsequently correlated these results with the existence of anemia (a common complication in hemodialysis patients), and macrocytosis. Methods: In 29 chronic hemodialysis patients, active H. pylori infection was diagnosed using two different methods regardless of digestive symptoms: by searching for bacterial antigens in stools and by the detection of urea breakdown through breath testing. If these results were non-coincident, gastroscopy was performed and antral biopsies obtained. Patients were subsequently divided into group A ( H. pylori-positive, n = 8, 28%) and group B ( H. pylori-negative, n = 21, 72%). The corresponding initial values of erythrocytic folic acid, vitamin B<sub>12</sub> and homocysteine prior to the first hemodialysis session of each patient were retrospectively collected. Results: Vitamin B<sub>12</sub> levels (normal 200– 900 pg/ml) were significantly lower in group A compared to group B (225.4 ± 111.9 vs. 707.9 ± 258.3 pg/ml, p < 0.011). In group A, 5 patients (63%) had vitamin B<sub>12</sub> deficiency (154 ± 24.6 pg/ml). Baseline hematocrits, erythrocyte folic acid and serum homocysteine levels were not different between the groups, but mean corpuscular volumes were significantly higher in group A compared to group B (109.7 ±14.1 vs. 91.8 ± 8.8 fl, p = 0.002). Conclusions: H. pylori-positive chronic hemodialysis patients may present with lower vitamin B<sub>12</sub> blood levels and macrocytosis. H. pylori infection should be suspected in this population when low or low-normal vitamin B<sub>12</sub> levels or macrocytosis exist.