A short overview of respiration monitoring methods has been presented in this master thesis. The influence of geometry of capacitive sensor electrodes on its characteristics was examined by means of electrostatic simulations and the format that achieves sufficient sensitivity and linearity was proposed, with additional benefit of being small and easy to produce. The characteristic obtained by simulation was compared to the characteristic measured on the sensor prototype. Components of the electronic system were chosen to allow continuous measurement of the sensor capacitance. The capacitance is measured by AD7746 integrated circuit, which provides high measurements resolution. The system is based on an ultra low power MSP430FR5969 microcontroller, and a Micro SD card is used for data storage. A user interface that allows system configuration and downloading recorded data is presented through an Android application running on a smartphone, which connects to the system via RN4020 Bluetooth LE module. Particular attention was paid to low power consumption and system compactness so all the components, including switching voltage regulator and integrated circuit for charging lithium batteries, are placed on a printed circuit board as small as 42 mm x 24 mm. The developed system can run continuously for several days powered by a single 400 mAh Li Po battery.