The effects of electron beam irradiation on thermal, mechanical and morphological properties of natural rubber/starch blends were investigated. The results of thermogravimetric analysis indicated that the thermal stability of natural rubber was improved by the addition of modified starch and by irradiation. On the other hand, thermal stability of irradiated natural rubber and natural rubber/unmodified starch blends is lower than that of pure natural rubber. The tensile strength of natural rubber (2.01MPa) was improved to 3.82MPa with the addition of 5phr unmodified starch. There was a further increase from 2.01MPa to 6.44MPa when 5phr modified starch was used.