Introduction. Leiomyoma is a benign tumor, the source of which is smooth muscles of the internal organs. This neoplasm is rare in children. Leiomyomatosis of the gastrointestinal tract is most often asymptomatic; it is clinically manifested when the size of the formation reaches more than 4 cm. The most common symptoms are abdominal pain and a palpable formation in the abdominal cavity. Surgical removal is the method of choice for most leiomyomas.Description of clinical case. This article describes a clinical case of leiomyomatosis of esophagus and rectum in a child who had suffered of abdominal pain, constant constipation and dysphagia since early childhood. The correct diagnosis was put several years later after the onset of the disease. Upon examination, a solid formation was found in the anal area. The examination also revealed a volumetric formation in the submucosal layer of the rectum, causing a narrowing of its lumen, as well as a large-sized formation in the thoracic cavity, causing esophageal stenosis. The first stage of surgical intervention was to place colostomy and to take biopsy of the rectal tumor. The second stage one month later was extirpation of the esophagus affected by the tumor, plastic surgery of the esophagus by the stomach. The morphological picture corresponded to leiomyomatosis. The third stage – extirpation of the rectum which was performed at A.N. Ryzhykh State Medical Center.Conclusion. This clinical case is one of few syndromic variants of leiomyomatosis described in the literature. Surgical intervention is the basic option for treating patients with non-epithelial neoplasms of the gastrointestinal tract. Active surgical tactics in benign tumors are due to high risk of developing or developed life-threatening complications.