Aim. Purpose of the study. Using the In-Check DIAL G16 device, determine the values of peak inspiratory flow (PIF) in bronchial asthma (BA) to assess the suitability of the inhaler used to the patient's capabilities and select the optimal inhaler. Design. Cross-sectional cohort study. Materials and methods. 60 patients with asthma were examined: 16 people with complete and 22 with partial control of the disease, 22 people with exacerbation of asthma. The control group consisted of 29 healthy people. Among patients with asthma, elderly women predominated. The patients were diagnosed with various asthma phenotypes: mild — in 7, moderate — in 34, severe — in 19 people. 16 out of 22 patients had a severe exacerbation of the disease. The determination of PIP is carried out using the In-Check DIAL G16 device. Results. Limitation of PIP was detected with complete control of asthma in 6.25–56.2%, with partial control — in 9.1–59.1%, with exacerbation of the disease — in 9.1–86.4% of cases, depending on the level of resistance of the device. Conclusion. Inhalation therapy for asthma can be personalized based on direct measurement of PIP using devices such as In-Check DIAL G16, which will allow treating physicians to select an inhaler in different periods of asthma, taking into account the degree of control, the period of the disease, the severity of bronchial obstruction and the individual characteristics of the patient. In order to optimize inhalation therapy for asthma, it is recommended to replace a powder inhaler with a high resistance device (R3–R5) with an inhaler with a low resistance (R0 — metered dose aerosol inhaler, respimat, R1 — breathhaler), and in case of exacerbation of the disease — use of a nebulizer.In order to optimize inhalation therapy for asthma, it is recommended to change the PI with a high resistance device (R3–R5) to an inhaler with a low resistance (R0 — MDI, respimat, R1 — breezhaler), and in case of exacerbation of the disease, use a nebulizer. Keywords: peak inspiratory flow, spirometry, bronchial asthma, inhaler.