Abstract Background and Aims Proton Pump Inhibitors are widely used in haemodialysis patients for the prevention and treatment of uremic gastritis, peptic ulcer, gastritis, esophagitis and gastro oesophageal reflux. Hypomagnesaemia is reported recently in some patients who abuse intake of Proton Pump Inhibitors (PPIs) but this problem is still not well studied yet. Our study aims to evaluate the chronic toxic effect of Proton Pump Inhibitor on Magnesium level in Egyptian haemodialysis patients, especially those who suffer from abuse of intake without medical prescriptions. Method The study was conducted at the haemodialysis centre and clinic of Alzawya One-Day Surgery Hospital in Cairo including 60 end stage renal disease patients after their consents and approval of ethical committee in our hospital. PPIs use and duration were investigated. The patients were dialyzed using a dialysate magnesium level of 0.5 mmol/L and Calcium level 1.5 mmol/L in all groups, after at least one month of haemodialysis with the mentioned dialysate, laboratory tests were performed. The patients participating in this study after their consents were divided into 3 groups: • Group A: - 20 patients on Proton Pump Inhibitors regularly with long term intake for more than 6 months on high dose above or equal280 mg/week [1] • Group B: -20 patients on Proton Pump Inhibitors irregularly for less than 6 months on low dose below 280 mg/week. • Group C: -20 patients not intake Proton Pump Inhibitors. The magnesium level in haemodialysis patients was evaluated by comparison between the 3 groups, and its correlation with duration of its use, Calcium and Phosphorus level in blood. Dialysate magnesium and calcium concentration in all groups were fixed and abuse of intake of PPIs without medical prescription in the participated patients was evaluated. Results Show highly statistically significant higher mean value in Non-intake of PPI group, followed by PPI intake ≤6m group and the lowest value in PPI intake >6m group according to magnesium “mg/dl”, with p-value (p<0.001). There is no statistically significant difference between groups according to calcium “mg/dl”; with p-value (p>0.05). Conclusion Proton Pump Inhibitors regularly with long term intake for more than 6 months on high dose above or equal 280 mg/week associated with hypomagnesaemia. So we recommend stoppage of abuse intake of PPIs in haemodialysis patients.