The potential effect of zinc supplementation on kidney functions, hematological parameters, parathyroid hormone and minerals was investigated in hemodialysis patients. Thirty patients in the age between 35 to 60 years who were on regular hemodialysis (HD) for more than three months, three times per week for 4-6 hours in each session received zinc supplement daily 250 mg (zinc citrate) /day (100 mg elemental zinc) for two months. Blood samples were collected at zero time, and at the end of this study, before hemodialysis from each patient. The results indicated that, supplementing hemodialysis patients with zinc caused a highly significant (P<0.01) decrease in the levels of serum urea, creatinine, uric acid, phosphorus and potassium. Significant (P<0.05) decrease was recorded in levels of white blood cells (WBC) and TIBC, compared to patient's status before zinc supplementation. On the other hand, zinc supplementation caused a highly significant (p<0.01) increase in the levels of mean corpuscular hemoglobin concentration (MCHC), calcium and zinc and significant (P<0.05) increase in the levels of hemoglobin (Hb). The obtained results suggested that supplementing hemodialysis patients with zinc may cause improvement in kidney functions and hematological parameters.