RESUMO
A urogenital sinus is a common channel into which both the urethra and genital tracts open. Occasionally there might be transverse obstructing membrane leading to hydrometrocolpos from either uterine secretions or urine. Although the presentation is varied, a neonatal presentation of a large hydrometrocolpos mimicking gross ascites is rare. A 3-day-old female infant was referred to us from periphery as a case of gross ascites of unknown cause. Patient was having rapid and shallow breathing and had gross ascites. The patient was evaluated and was diagnosed to have large hydrometrocolpos. To avoid unnecessary delay in diagnosis and proper treatment the possibility of hydrometrocolpos secondary to urogenital sinus presenting as generalized abdominal distension should be kept in mind. A focused genital examination can help achieve the diagnosis