To describe the causes and outcome of urinary retention in children and assess its prevalence by gender and age.The medical records of all children (aged18 years) who presented to the emergency room with acute urinary retention from 2000 to 2012 were reviewed. Patients with postoperative urinary retention, a known neurologic disorder, and neonates were excluded. Data were collected on patient demographics and cause, treatment, and outcome of the urinary retention. Findings were evaluated and compared by age and gender.The study group comprised 42 boys (75%) and 14 girls (25%). Median follow-up time was 25 months. Causes of urinary retention were mechanical obstruction in 14 patients (25%), infection or inflammation in 10 (18%), fecal impaction in 7 (13%), neurologic disorders in 6 (11%), gynecologic disorders in 4 (7%), and behavioral processes in 3 patients (5%); 12 patients (21%) were idiopathic. All patients with mechanical obstruction were boys, of whom 5 had a pelvic tumor. Age distribution was bimodal: 29% of the events occurred between ages 3 and 5 years, and 32%, between ages 10 and 13 years. Fifteen children underwent surgery. Three children required continuous catheterization during follow-up.Urinary retention in children is characterized by a variable etiology and bimodal age distribution. The high rate of severe underlying disease is noteworthy and should alert physicians to the importance of a prompt, comprehensive, primary evaluation of this patient population in a hospital setting to initiate appropriate treatment and avoid complications.