The effects of ethylene-evolving preparations—2-chloroethylphosphonic acid (2-CEPA), the new generation binary preparation ethacide, and the specific inhibitor of ethylene biosynthesis aminooxyacetic acid (AOA)—on the ethylene evolution by banana (Musa sp.) fruits at various ripening stages and the content of protein inhibitor of polygalacturonase (PIPG), associated with prevention of fruit tissue softening, were studied. It was demonstrated that the ripening stage was of significant importance for the results of treatment with the mentioned preparations. Their effects were most pronounced in the fruits of medium ripeness. 2-CEPA and ethacide increased the ethylene evolution in banana fruits on the average by 25–30%. AOA treatment decreased the ethylene evolution in these fruits by 30%. The PIPG content in fruit pulp was insignificant; 2-CEPA almost did not change its content in banana skin, while ethacide and AOA somewhat decreased it. Consequently, the regulators of ethylene biosynthesis have a potential for optimizing the state of banana fruits during storage and sale.