The aim of the present work is to study the effect of He-Ne laser (632.8 nm, 2 mm spot diameter, 30 mW , and continues wave) on the properties of human blood during different storage periods and seeking for the optimum laser dose(0.198 J/cm3)to enhance blood shelf life. Human blood from five healthy donors was collected in human blood bags under the supervision of the central blood bank. The control and treated samples (by three doses of He-Ne laser) were stored in central blood bank refrigerator at 2-60C.The collected blood was divided into 4 groups, one for the control sample and the three other groups for the irradiation with different doses of He-Ne laser (0.0287, 0.0563 and 0.198 J/cm3. Each group was subdivided into 6 samples to perform during storage days (9, 24, 30, 35, 42, & 50). The measurements of the fragility (Ϝ) and viscosity (η) values of all samples during the storage days suggested that the He-Ne laser at a dose 0.198 J/cm3is working to increase the resistance of the membrane of the red blood cells (RBC) and consequently the storage period increases form 35 day to 42 days. I n addition to viscosity for human blood before and after exposure to He-Ne laser dose of 0.198 J/cm3 reflects the validity of the blood during the storage period. The obtained data proved that the ability to use the recommended He-Ne laser dose of 0.198 J/cm3 the rheological properties and prolong the storage period of human blood from 35 days to 42 days.