Objective: to evaluate the efficacy and safety of argon plasma coagulation for endoscopic hemostasis in Mallory-Weiss syndrome. Materials and methods: on the basis of a clinical observation of a patient admitted to the emergency department of the State Budgetary Healthcare Institution of the Moscow Region of the Children’s Central City Hospital with complaints of vomiting of scarlet blood, dark stools, weakness, dizziness. The patient underwent emergency EGDS. Results: According to the EGDS data, a linear mucosal rupture was detected in the lower third of the esophagus along the posterior wall with a transition to the stomach cardia along the lesser curvature, about 8-9 cm long (5 cm in the esophagus, 3-4 cm in the stomach), up to 2 cm deep. -3 mm, from the rupture there is a flow of scarlet blood of medium intensity, in the bottom of the defect, fibers of the submucosal and muscular layers were determined. Endoscopic hemostasis was performed: argon plasma coagulation of the rupture of the mucous membrane of the esophagus and stomach. Against the background of endoscopic treatment by argon plasma coagulation in a patient with a long rupture, hemostasis was achieved and surgical treatment was avoided, which could aggravate the condition and lengthen the treatment time. Conclusions: Argon plasma coagulation as a non-contact method of hemostasis has a limited penetration depth and is safer and more effective than other (contact) electrocoagulation methods, where, as a rule, it is difficult to control the depth of exposure. The use of this method improves the efficiency of endoscopic hemostasis, reduces economic costs, and reduces the patient’s stay in bed.