Causes and outcomes of children diagnosed with hydronephrosis in resource-limited countries with a low utilization of antenatal ultrasonography remain unexplored. We performed a retrospective, crosssectional study of all paediatric patients diagnosed with hydronephrosis and managed at a tertiary care center in Karachi, Pakistan between 2005 and 2010. Data relating to demographics, clinical features, etiologies and treatment modalities were systematically collected. Of a total of 234 cases (74.4% male), 83 (35.5%) and 42 (17.9%) were neonates and infants respectively. Congenital urinary tract pathologies were noted in 192(72.2%) patients, of which only 96(50%) had undergone foetal ultrasonography and 77(40.1%) first presented after the age of 1 year. At a median follow-up of 4 years, 24(12.5%) of these patients had evidence of renal dysfunction. Worse urologic outcomes in this study were most likely attributable to delayed diagnosis of congenital urinary tract abnormalities.