Bioethanol is one of the most employed liquid biofuels due to the easy ‎adaptability of this fuel to existing engines and because this is a ‎cleaner fuel with a higher-octane rating than gasoline. Among the ‎widely used substrates for ethanol production is sugarcane molasses. ‎Unsuitable storage of molasses results in deterioration of fermentable ‎sugars consequently ethanol yield quality and efficiency. The present ‎study aimed to shed light on the effect of the storage period on the ‎efficiency of sugarcane molasses and its effect on ethanol fermentation ‎efficiency in distillery factories. The results showed that the total ‎fermentable and non-fermentable sugars involved in sugar cane ‎molasses varied between samples that were collected according to the ‎location source. Also, ethanol yield and fermentation efficiency were ‎different in the fermented molasses media which contained the same ‎concentration of fermentable sugars. About 2.6511.20% of ‎fermentable sugars in molasses were lost when stored under different ‎temperatures. The loss was increased with the increasing storage ‎temperature. Most of the loss happened in the first two months, ‎especially at high temperatures. The decrease in ethanol yield and ‎fermentation efficiency was affected sharply in the molasses storage at ‎high temperatures than the low ones. From this study, the suitable ‎storage temperature must not exceed 40°С to maintain molasses ‎quality and avoid molasses deterioration by heat in temperatures.