The purpose of the study was to determine the predictors of severe bronchiectasis (BE) not associated with cystic fibrosis (CF) in children and to evaluate the effectiveness of a stepwise complex conservative therapy. Materials and methods of the study: study design – multicenter cohort prospective pilot study. 67 hospitalized pediatric patients aged from 11 months up to 17 years old (52% boys and 48% girls) with BE caused by previous pneumonia (22%), primary ciliary dyskinesia (22%), bronchial asthma (13%), Williams–Campbell syndrome (7%), bronchial foreign bodies (7%), gastroesophageal reflux disease (6%), bronchopulmonary dysplasia (6%), postinfectious bronchiolitis obliterans (5%), allergic bronchopulmonary aspergillosis (3%), chronic granulomatous disease (3%), AIDS (1%), protracted bacterial bronchitis (1%), and brainlung- thyroid syndrome (1%) were observed. Predictors of severe BE were determined based on a comparison of groups of patients with mild (up to 4 exacerbations of BE per year) and moderate (from 4 to 6 exacerbations) course of BE (n=31) and patients with severe course of BE (>6 exacerbations per year, n=36). At the second stage of the study, in patients with changes in the severity of the course of BE, who were followed in dynamics (n=42), the frequency of exacerbations was assessed during the year after the appointment of a stepwise complex conservative therapy, which included, depending on the severity, daily drainage massage, exercise therapy, auxiliary devices for the respiratory tract clearance, long-term anti-inflammatory azithromycin, inhaled/ intravenous antibiotics, and/or respiratory support. Results: the clinical picture of severe BE occurring with >6 exacerbations per year compared with mild/moderate course of the disease (≤6 exacerbations per year) is characterized by a statistically significantly more frequent registration of dyspnea (86% and 45%, p<0.001), exercise intolerance (69% and 39%, p=0.012), wet rales (89% and 61%, p=0.011), finger clubbing (17% and 0%, p=0.027). The prognostic model for determining the likelihood of severe BE not associated with CF in children includes the age of manifestation, a positive result of bacteriological examination of sputum/aspirates from the respiratory tract, localization of BE in the middle lobe of the right lung and/or lingual segments, and dyspnea. The appointment of gradual conservative therapy for BE, depending on the severity/frequency of exacerbations, makes it possible to statistically significantly reduce the severity of BE (p<0.001) and the median of exacerbations during the year from 9.00 [3.25–12.00] before treatment to 2.00 [1.00–3.00] after treatment (p<0.001). Conclusion: BEs are heterogeneous in severity, which determines the choice of therapy. Conservative therapy of BE not associated with CF in children has a stepwise principle depending on the severity of the course. Its appointment could therefore reduce the frequency of exacerbations. © 2022, Pediatria n.a. G.N. Speransky. All rights reserved.