Background: abnormal electrolytes concentrations in asthma patients can be attributed to low intake or secondary to asthma medications. Objectives: to identify the pattern of changes in electrolytes concentrations among asthmatic patients and to detect correlations between concentrations of electrolytes and pulmonary function measurements. Materials and Methods: the study involved a control group of 56 nonasthmatic subjects matched for gender and age with a study group of 100 patients with a medical history of asthma but no other respiratory diseases. IQ TQ Spirometer was used to assess pulmonary function according to ATS/ERS standards. Sodium, potassium, calcium and magnesium concentrations were measured from venous blood samples. Results: There were significant positive correlations between potassium concentration and FEV1, FEF50%, FEF25-75% (P < 0.05) and negative correlation between sodium concentration and FEV1%, FEV1/FEV6, FEF25%, FEF75%, FEF25%- 75%, FEF85%-75% (P < 0.05). None of the electrolytes showed significant differences in the mean when asthmatic patients were compared with control group (P > 0.05). Conclusion: sodium and magnesium concentrations of asthmatic patients showed no significant differences in the means when compared with the control group, but elevated levels of sodium were associated with poor ventilatory function. High levels of potassium were associated with better pulmonary ventilation.