The incidence of appendicular peritonitis (AP) is 3-4 % among all acute surgical diseases in children, and the structure of acute appendicitis in recent decades fluctuates within 10-15 %. Timeliness and informativeness of acute abdomen diagnostics remain important tasks of clinical practice. The use of laparoscopy with its possibility of diapeutic approach allows to diagnose and eliminate the cause of the disease. On the basis of the surgical department of the Children's City Clinical Hospital No. 1 in Nizhny Novgorod. In the period from 2018 to 2022, 126 (11.2%) patients with various types of AP were treated in Nizhny Novgorod. All children were examined with assessment of general and local status, laboratory tests were performed using unified methods developed for practical healthcare. In complicated or doubtful cases, ultrasound of the abdominal cavity organs was performed (Vivid-7 of expert class using high-frequency transducers: convex (frequency up to 5 MHz) and linear (frequency up to 10 MHz). Local forms of AP prevailed – 90 %, of which appendicular abscess was found in 35 % of observations. Data of anamnesis, examination of patients, assessment of purulent-inflammatory markers in complicated and controversial situations were resolved by ultrasound of abdominal cavity organs. Instrumental diagnostics allowed them to detect anechogenic contents (effusion), delimited areas of absceding between the intestinal loops, perforation defect of the appendix wall, periappendicular abscess forming. Within the framework of surgical correction the priority was given to laparoscopy (59.5 %), a modern therapeutic and diagnostic method with a diapeutic approach. Open interventions were used in 51 (49.5%) patients, of which: Sprengel's access was performed in 31 (61%) patients, Volkovich-Dyakonov was used in 19 (37%) cases, midline laparotomy was performed in 1 child. Analysis of the results of bacteriological studies allowed us to identify the leading pathological pathogens belonging to Gram-negative or Gram-positive flora. In the postoperative period, therapy corresponding to the treatment of patients with peritonitis was prescribed. Evaluation of bacteriological examination revealed that Enterobacteriaceae (87%), non-fermenting bacteria (72%) were susceptible to all antibiotics. However, the highest susceptibility (73 %) was noted to cephalosporins. All children were discharged home in satisfactory condition, with an average bed-day of 12.32 ± 2.4.