Vaginal malformations can be diagnosed by ultrasound in a large number of cases. The prevalence of uterovaginal aplasia usually reported in the literature is 1/4000 to 1/10,000. Objectives: We tell you about the difficulties of diagnosis with ultrasound, the difficulties of managing our case of vaginal aplasia. Observation: This was a 20-year-old patient saleswoman, single. History of the disease: was marked by cyclic pelvic headache for 6 months with primary amenorrhea. She has no particular medical-surgical history. On physical examination: Secondary sexual characteristics were developed. On inspection of the vulva, normal pubic hair was noted. Examination of the vulva showed the labia majora and labia minora present and normal-looking. A hymen could not be identified and there was no visible vaginal opening. Faced with this clinical and paraclinical symptomatology, we made the diagnosis of vaginal agenesis. The ultrasound showed a uterus measuring about 92x71x62 mm, its parenchyma is homogeneous, its contours are regular. The presence in the uterine cavity at the corporeofundic level of a homogeneous echogenic collection of about 66.5 cc (69x35 mm). Note the congenital malformation of the cervix with agenesis). The Surgical Procedure Performed is vaginoplasty. Conclusion: Ultrasound of uterine malformation is difficult and requires some experience from the sonographer.