Science; medicine; clinical diagnostics; biotechnologies, including those in food and beverage industries; as well as environmental technologies need highly selective, sensitive, rapid, and reliable methods of identifying the key ingredients or metabolites which determine the quality of the product or serve as markers for diseases, the physiological state of human organism, or environmental safety. Biosensors are the most promising tool for these aims. Although most of the created biosensors are based on using enzymes as biocatalytic elements, cell sensors, especially microbial ones, have been actively developed only in recent years. A microbial biosensor consists of a transducer in conjunction with immobilized viable or nonviable microbial cells, an economical substitute for enzymes. The target analyte is usually either a substrate or an inhibitor of cell metabolism. In this review, the main achievements in the elaboration of microbial sensors, based on yeast cells, are described, and perspectives of their usage in clinical diagnostics and food control are discussed.