Single cell protein (SCP) is a good source of essential amino acids. This study aimed to utilize some date by-products such as date fruit flesh to produce single cell protein.  Fruit flesh of three unknown dates and three date varieties were used to produce a single cell protein by Saccharomyces cerevisiae ATCC64712 under different condition (sugar concentrations in the extract media, temperatures and pH values). The results showed that the optimum production of the biomass (42.85 g/l) was produced from date extracts media at 18% sugar, 30˚C and pH 4.5. To reduce nucleic acids content in the biomass, heat shock was used. The effect of heat shock on protein content and nucleic acids percentage for the studied yeast strain was 75.83%, and the maximum reduction of nucleic acids was observed at pH4 and 60°C for 30 sec with 20.88% loss of its protein content. The present study provides evidence that date flesh is a great source for single cell protein that can be used in variable fermentations. Additionally, single cell protein has a high level of essential amino acids such as lysine, methionine and threonine. This source of protein has been proved a good replacement of other expensive protein sources like fish and soybean meals. Therefore, conclusion can be made that single cell protein can easily replace traditional (plant and animal) protein sources in human, animal as well as fish diets without any detrimental effect.