The solid-phase photocatalytic degradation of low density polyethylene (LDPE) with sol-gel synthesized TiO2 nanoparticles as photocatalyst was investigated under ultraviolet (UV) irradiation in ambient air conditions. TiO2 nanoparticles were synthesized by optimizing various parameters and the TiO2 nanoparticles were dispersed in LDPE using cyclohexane solution. This TiO2-PE nanocomposite was made in the form of thin films of 40 m size by facile solution casting method and studied photodegradation of these films. A comparative study on the photodegradation of two different sized TiO2 incorporated LDPE under UV radiation was carried out. Polyethylene film incorporated with TiO2 nanoparticles of size 50nm showed higher degradation rate under UV radiation. Partial oxidation was confirmed from the IR spectrum of the TiO2 incorporated polyethylene film after radiation exposure.SEM analysis and AFM nanoindentation measurements confirms the degradation. A possible mechanism of TiO2 assisted degradation of the polyethylene matrix has also been proposed.