Alterations of serum copper concentrations are commonly found in patients suffering from gastrointestinal infections and with hepatic, renal, cardiovascular and malignant diseases. In this study, we aimed to investigate the changes of total content of the essential element of copper level in patients infected with Giardia intestinalis. Copper concentration was measured in 64 patients who were positive for intestinal parasite of G. intestinalis. Scores obtained for the positive samples, their age and sex, matched 60 G. intestinalis negative healthy controls. The mean concentration of copper in serum was significantly higher in G. intestinalis positive subjects than in their controls both in females (p < 0.05) and males (p < 0.05). No correlation could be demonstrated between age and mean value of copper in G. intestinalis positive in both females and males control (p > 0.05). Copper level was found to be clearly increased in the patients infected with G. intestinalis compared to controls. Although, our findings suggest altered element metabolism due to the pathophysiologic changes of G. intestinalis, a detailed biochemical and molecular studies on large sample size are needed to put forward a relationship between G. intestinalis (may be other parasitic diseases) and serum element level changes.