In this research for selecting best optimum linear low density polyethylene content for bitumen modification. 80/100 Pen bitumen were used as the control sample and linear low density polyethylene (LLDPE) were blended with 80/100 pen bitumen to prepare a modified mix. The concentrations of LLDPE polymer in the blends were 4, 5 and 6 by weight of bitumen. Conventional test which includes penetration, softening point, ductility, temperature susceptibility tests were conducted using the control 80/100 and LLDPE modified binders. Also storage stability test were conducted to access the stability of the control and LLDPE modified binder. The results indicate that 6 LLDPE modified binder offers the best results compared to control, 4 and 5 LLDPE modified binders when they were investigated in terms of conventional properties. Storage stability test result shows that phase separation might occur in all the polymer modified binders during storage or transportation especially at higher temperatures. © 2016 Taylor & Francis Group, London.