Introduction:
The role of magnesium defi ciency in metabolic syndrome pathophysiology is one of the issue presently discussed in the literature. The others electrolyte disturbances in this syndrome are also the object of interest. The aim of the study was to analyze electrolyte equilibrium disorders in patients with metabolic syndrome.

Material and Methods:
The study group consisted of 36 (29 females and 9 males) patients with metabolic syndrome hospitalized in the Internal Medicine Wards of District Hospitals in Blachownia and Pajęczno and 29 (10 females and 19 males) healthy volunteers (control group). The metabolic syndrome was diagnosed according to IDF (2005) criteria.

Results:
In contrast to the sodium and potassium serum magnesium level was signifi cantly lower in patients with metabolic syndrome than in the control group. Moreover there was a negative serum magnesium correlation between waist circumference and body mass index among patients with metabolic syndrome. There were positive correlations between serum sodium and systolic and diastolic blood pressure, serum potassium and triglycerides concentrations in the group with metabolic syndrome. The foregoing correlations were not found in the control group.

Conclusions:
1. Serum magnesium was significantly lower in patients with metabolic syndrome than in the control group. 2. The correlation between serum magnesium and waist circumference, body mass index shows the possible abdominal fatty tissue influence on magnesium equilibrium among patients with metabolic syndrome. 3. The positive correlation between serum sodium and systolic and diastolic blood pressure points the possible role of sodium in pathogenesis of hypertension in metabolic syndrome.