Gitelman’s syndrome is a type of hereditary tubular disorder, which is caused by inactive mutations in the gene, which encodes thiazide sensitive sodium chloride cotransporter (SLC12A3) in the distal convoluted tubule. Biochemical characteristic is comparable to effect of thiazide diuretics: hypokalemia, hypomagnesaemia, hypocalciuria, hypokalemic alkalosis and blood pressure is normal or lower. Gitelman’s syndrome is typically diagnosed accidentally (hypokalemia) in adolescents or adults and the course is benign. If present, the most prominent symptoms are muscular fatigue or occasional tetany. Treatment includes magnesium and potassium salts and potassium saving diuretics. We report here a case of an adult patient with Gitelman’s syndrome. The patient was a bearer of three heterozygote mutations in the gene, which encodes thiazide sensitive sodium chloride cotransporter (SLC12A3) in the distal convoluted tubule.