Introduction. Herlyn-Werner-Wunderlich syndrome (HWW) is a rare congenital anomaly of the female urogenital tract that associates Müllerian duct anomalies with mesonephric duct anomalies. The triad of uterus didelphys, obstructed hemivagina, and ipsilateral renal agenesis characterizes this syndrome. The aim of the study. To analyze the clinical characteristics, diagnosis and treatment of patients with HWW syndrome. Materials and methods. We ret ros  pect ively reviewed medical records of 49 consecutive ca-ses with hematocolpos. Results. A total of 13 patients, mean age 15.9±0.8 years (95% CI:14.16/17.53) were admitted to our de part-ment complaining progressive cyclic abdominal (vaginal) pain and dys menorrhea (100%), urinary retention (n=3, 23.1%) and cons ti pa-tion (n=1, 7.7%). Pelvic examination revealed obstructed he mi va-gina with elastic vaginal and pelvic mass. Pre-operative evaluation included US and MRI which revealed abnormalities consistent with HWW syndrome (right vs. left side - 69.2% vs. 30.8%) and hematocolpos (hematometrocolpos) with max. size - 116.1±12.7 mm (95% CI:88.40–146.6), min. - 72.5±6.6 mm (95% CI:58.77-86.31). According to characteristics of HWW syndrome, complete (n=5, 38.5%) or incomplete (n=8, 61.5%) obstruction of the hemivagina was detected. Surgical excision of the septum and drainage of the obstructed vagina (hematocolpos) relieved the symptoms. During follow-up: the complete resolution of dysmenorrhea and no recurrence of hematometra or hematocolpos. Conclusion. HWW syndrome is a rare condition. Early and accurate diagnosis of this syndrome is important so that adequate and prompt surgical therapy (excision of the vaginal septum) can provide relief of pain and prevent further complications (endometriosis, infertility).