Hydrometrocolpos is accumulation of secretions in the vagina and uterus, caused by excessive intrauterine stimulation of the infant's cervical mucous glands by maternal oestrogen in the presence of an intact hymen (Wilson et al 1978). Hydrocolpos is dilatation of the vagina proximal to a congenital obstruction. If the uterus is also dilated, the condition is called hydrometrocolpos. Most cases of hydrocolpos are associated with an imperforate hymen that forms a thin bulging membrane between the labia. Though many cases of hydrometrocolpos have been reported in literature, there is no case report which shows classical ultrasound findings and follow up ultrasound scans to show the involuted uterus. We are presenting a case report whose diagnosis was established on ultrasound. This case highlights the value of ultrasound in diagnosing this condition and excluding other associated renal anomalies.