Idiopathic hypercalciuria is the most common metabolic disorder leading to urolithiasis. The following factors are involved in its pathogenesis: environmental and dietary factors, kidney defects leading to excess loss of calcium in urine, conditions characterised by increased bone calcium resorption, and genetic mutations impairing vitamin D metabolism. The severity of hypercalciuria may vary, from vitamin D intoxication, through nephrocalcinosis, urolithiasis, hypercalciuria, to milder forms, which occur during vitamin D supplementation. Hypercalciuria may produce non-specific symptoms, such as erythrocyturia, haematuria, sterile leukocyturia, and urinary tract infections. We present a case of a 10-year-old girl with recurrent urinary tract infections. Following the exclusion of urinary tract defect and urinary bladder dysfunction, the patient was diagnosed with renal hypercalciuria. Genetic testing confirmed CYP24A1 mutation. Treatment with thiazides resulted in calciuria normalisation and resolution of recurrent urinary tract infections. Conclusions: Genetic hypercalciuria should be suspected in patients with recurrent urinary tract infections.