This work summarizes and discusses the monitoring of various bioprocesses with the use of electronic tongue (ET) systems. These devices coupling sensor arrays with pattern recognition units allow for the qualitative and quantitative analysis of complex composition liquid samples based on their unique “fingerprint”, i.e. sensor response pattern. Such an approach provides reliable results in real time, with the use of simple, inexpensive tools – therefore ET systems seem to be an interesting alternative to classical control of bioprocess run based on chromatography or spectrophotometry. The presented attempts focused on the development of different sensor arrays based on flow-through potentiometric ETs as well as hybrid ET systems dedicated to the monitoring of biogas production, alcohol fermentation and Aspergillus niger fermentation.