Aim. To assess ergonomic properties of a long-term ECG monitoring device from the standpoint of its usability and reliability of data recording.Methods. Three generations of the long-term ECG monitoring device were tested. 86 volunteers (30 women) were recruited in a study. Over 100 ECG recordings were collected to estimate ergonomic properties. A set of measures to improve the ergonomic properties was recommended after each generation testing. After the upgrading, the device was entering the next stage. The overall study duration was 3 years.Results. The assessment of ergonomic properties of the long-term ECG recording device resulted in the improvement of the device case, universal electrodes, safe data transmission channel, and a user-friendly instruction manual. The software package for data processing was improved and allowed the introduction of remote data transmission to physicians.Conclusion. The device corresponds to all standards of ergonomics and usability. It received the Federal Health Care Supervisory Agency (Roszdravnadzor) approval.