The study aimed analyzing case histories of 36 children (21 girls and 15 boys), from between 3 weeks and 17 years old, with urinary tract abnormalities, admitted to the Pediatric Nephrology Department for renal stone disease within a 5-year period (1995-1999). Most common clinical manifestations, requiring further urinary tract investigation, were: pain, urinary tract infections caused mainly by Gram-negative bacteria, and erythrocyturia. Most frequent anomalies observed in our patients were those resulting in urinary outlet obstruction. Disturbances in uremic acid and oxalate metabolism were abnormalities we have often found in the examined children. The majority of patients underwent a successful conservative treatment. The obtained results indicate that disorders in the urine flow are main risk factors for crystallization in children with urinary tract abnormalities.