This scientific opinion of the EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF Panel) deals with the safety assessment of zinc oxide, nanoparticles, uncoated (FCM No 1050) and coated with [3-(methacryloxy)propyl] trimethoxysilane (FCM No 1046), for use as a transparent ultraviolet light absorber in all polyolefins at a maximum content of 2 % and 3 % for the uncoated and the coated species, respectively. The substance is used as a powder in nanoform. In the final polymer, nanoparticles are still present but largely aggregated. The specific migration of the substance was tested from low-density polyethylene films, containing the maximum use level of the substance, into 3 % acetic acid and 10 % and 50 % ethanol for 10 days at 60 °C. Data from a stress test with iso-octane for 10 days at 20 °C was provided. Migration values into the different simulants and the microscopic analysis of swollen polymers demonstrate that there is no mass transfer of the zinc oxide in nanoform. In 2003 the Scientific Committee on Food established for zinc a no observed adverse effect level of 50 mg/day and an upper limit of 25 mg/person per day was recommended. The CEF Panel concluded that zinc oxide, nanoparticles, uncoated or coated with [3-(methacryloxy)propyl]trimethoxysilane, does not migrate in nanoform, and therefore the safety evaluation focuses on the migration of soluble ionic zinc. Available migration data for ionic zinc coming from the intended application are in compliance with the current specific migration limit (SML), but in combination with the dietary exposure from other sources the upper limit of 25 mg/person per day could be exceeded. For use of the coated form of zinc oxide, migration of [3-(methacryloxy)propyl]trimethoxysilane should be within the existing SML for this substance of 0.05 mg/kg.