Abstract <p>Long-term cardiac monitoring systems extend the diagnostic capabilities of stationary electrocardiographs (ECGs) and can monitor the functioning of the heart over a protracted period. There are numerous options for implementing long-term cardiac monitoring systems that differ from each other both structurally and functionally. However, all the systems used on the market have numerous disadvantages that do not allow combining the device with high-quality readings and convenient operation at the same time. In this study, the developed wearable long-term cardiac monitoring system is presented that registers 12 standard electrocardiogram leads. Electrical potentials are measured from the skin surface by a group of capacitive sensors connected by stretchable cables to the processing device, thereby excluding from the design long cables that are uncomfortable for the patient during prolonged use. The possibility is shown of transmitting an ECG via a USB cable, microSD card, or by the wireless pairing of the device via Bluetooth to a smartphone, as well as recording and transmitting the patient’s position and movement data for comparison with the electrocardiogram using a built-in MEMS sensor. The design and operation of the functional units of the system are described. The developed system is characterized by a low weight and small dimensions, which improves the patient’s experience during long-term cardiac monitoring, while maintaining the diagnostic capabilities for detecting various cardiovascular diseases.</p>