Hydrometrocolpos usually occurs in the neonatal period. The majority of cases are caused by vaginal occlusion by a transverse septum combined with cervical secretion. Although not well appreciated genital distension by urine may occur in some cases with a persistent urogenital sinus or cloaca. We report 3 cases of urinary and 8 cases of secretory hydrometrocolpos. The frequency of associated anomalies, especially in the urogenital tract, was high (9 of 11 patients), which was the most important factor in determining the morbidity and mortality. Of the patients 2 died, and 9 are alive and healthy, demonstrating that the prognosis of hydrometrocolpos is excellent. The diagnosis of hydrometrocolpos should no longer be difficult to determine. The most important step is a thorough vaginal examination, although modern imaging methods may be helpful. The aim of treatment is distal vaginal drainage, which can be achieved by a perineal procedure in most cases. Laparotomy is indicated only in cases of high vaginal atresia, which require a vaginal pull-through procedure.