Cocoa bean shell is a by-product of the food industry that is still underutilized. Due to its characteristic composition (fibers and polyphenols), it is increasingly being researched for use in the production of functional foods. In addition to bioactive compounds and components that can have a positive impact on human health, cocoa shells can also contain various contaminants, unwanted organic compounds that must be removed before using the shell in food production. In addition, cocoa shells, due to the high content of insoluble fiber, are difficult to mill. The aim of this dissertation was to determine the influence of high voltage electrical discharge (HVED) on the properties of cocoa shell and the possibility of solving these problems. HVED is a non-thermal technology based on the generation of electrical discharges directly in the solution between the discharge and ground electrode. Different frequencies, times and concetrations of cocoa shell in water suspension during treatment were studied. Subsequently, two different drying procedures were performed (in an oven at 60 °C and lyophilization) on HVED-treated shell (under selected conditions). The obtained results show that HVED had an improved retention of methylxanthines and certain polyphenols in cocoa shell compared to control samples. Also, there were significant changes of the fibers and chemical composition of the cocoa shell, as evidenced by FTIR-ATR analysis and differential scanning calorimetry. Furthermore, there was a decrease in the content of undesirable components and enterobacteria. Examination of various shell drying procedures (in an oven at 60 °C and lyophilization) showed that lyophilization had a more favorable effect on the properties of cocoa shell.