Arteriovenous malformations (AVMs) are vascular pathologies in which tissue trophism and blood outflow are disrupted due to the congenital or acquired absence of capillaries and the formation of a single conglomerate in which the arteries pass directly into the veins. Aim: to share our experience in the diagnosis and treatment of AVM of the colon in children. Material and methods. Clinical case No. 1. A 4-year-old girl was admitted to the N.F. Filatov State Clinical Hospital with a clinical picture of gastrointestinal bleeding (GCC). For the first time, an episode of stool with streaks of blood was observed at 2 years and 4 months. The examination revealed ulcerative colitis in the rectum, multiple erosions covered with fibrin were found. Long-term conservative therapy with no effect. Upon admission to the clinic, the child’s condition is moderate, the stool is light brown, and there is dark blood on top of it in the amount of 3-4 drops. According to ultrasound data, a thickening of the walls of the rectum with a slight increase in blood flow in them is determined above the anus. During the radioisotope study, an increase in the accumulation of RFP in the lower abdominal cavity was revealed. CT scans of the abdominal cavity and pelvis with contrast indicate increased vascularization of the walls of the middle and lower third of the rectum. Ultrasound of the sigmoid and rectum was performed: at a distance of 40 mm from the anus, an area in the rectal wall was visualized in which blood flow was increased during CDK, and venous vessels with arterial pulsation in them were also detected there. Endovascular angiography was performed, and intestinal AVM was detected (in the venous phase, dilated pathological veins can be traced projectively to the ampoule of the rectum). Taking into account the intensity of bleeding (5-6 times a day), it was decided to remove the pathological part of the colon. Laparoscopic resection of the sigmoid and rectum according to Swanson was performed in two stages. During the first stage, during the revision and mobilization of the colon at the level of the superior sigmoid artery, a large number of dilated vessels were found in the mesentery, and pathological vessels were also detected along the posterior wall of the rectum. On 4-5 postoperative days, the bleeding resumed, which indicated the formation of collateral blood flow. On the 14th day after stabilization, the second stage of Swanson surgery was performed - a direct coloctal anastomosis was performed. The bleeding continued. A decision was made to disconnect the rectum and apply an ileostomy. However, in the postoperative period, abundant mucous discharge with a hemorrhagic component remained from the rectum. Repeated angiography was performed - the vessel feeding the AVM was identified and embolized - the volume of bleeding decreased, but it was not possible to completely stop it. A decision was made to perform a colectomy and form an ileoanal anastomosis. Intraoperatively, marked lymphorrhea, tortuosity, and vasodilation of the mesentery were noted during intestinal discharge. In the postoperative period, blood in the stool was observed in the form of rare veins, which eventually disappeared. Clinical case No. 2. A 10-year-old girl was admitted to the clinic complaining of blood in her stool. It is known from the medical history that for 2 years the child has been worried about periodic pain in the left side of the abdomen. A year ago, the first episode of blood in the stool. During the examination, the diagnosis of UAC was established - conservative therapy was prescribed, against which remission was noted for about 3 months. Further, the resumption of GCC was noted, despite the ongoing treatment. A radioisotope study was performed, and an increased accumulation of RFP was detected in the left abdominal cavity. Upon admission, the condition is of moderate severity, the child is malnourished. The abdomen is soft on palpation, moderately painful in the left abdomen. The stool is mushy, with an admixture of blood and mucus, a tendency to diarrhea. According to the results of angiography, AVM of the colon was detected: in the descending part of the colon and in the rectum, the pathological tortuosity of small arterioles with increased capillary blood flow was contrasted. To eliminate life-threatening bleeding, a left-sided hemicolectomy with the formation of a colostomy was performed. Intraoperatively, telangiectasia was detected along the anterior surface of the rectum, the vessels in the colon and the left half of the intestine were dilated to 4-5 mm. In the postoperative period, the child had minor bleeding from the distal rectum. Clinical remission was achieved within 1 year. Discussion. It is believed that AVM occurs in 1 in 10,000 people, while in the literature, the localization of AVM in the colon or small intestine is described in no more than a hundred observations, of which 80% of cases are localized in the left half of the colon or rectum. The most common symptoms of this pathology are GCC, accompanied by the development of iron deficiency anemia. It is worth noting that AVM of the large intestine is often hidden under the guise of inflammatory bowel diseases. Children have been receiving inappropriate therapy for years, which can be misdiagnosed as drug resistance. Conclusion. The diagnosis of AVM is established using imaging research methods. In case of accidental detection of AVM, wait-and-see tactics are used due to the high traumatic nature of surgical treatment. If symptoms are present, endoscopic laser or thermocoagulation, resection of the affected area, or endovascular treatment is possible.