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, (FCM No 1050) for use as a transparent ultraviolet light absorber in unplasticised polymers at up to 2% by weight. The substance is added as a dispersion of the powder in nanoform. In the final polymer, nanoparticles are still present. The specific migration of the substance (determined as zinc) was tested from low-density polyethylene plaques containing 2% of the additive, into 3% acetic acid, and 10% and 50% ethanol for 10 days at 60ºC. Migration levels of zinc into these three simulants was 2.0, 0.05 and 0.06 mg/kg, respectively. In 2003, the Scientific Committee on Food established for zinc a no observed adverse effect level of 50 mg/person per day and an upper limit of 25 mg/person per day was recommended. Taking into account the knowledge about the diffusional properties of nanoparticles in polymers and the solubility characteristics of the zinc oxide nanoparticles, the CEF Panel concluded that the substance does not migrate in nanoform and therefore the safety evaluation should focus on the migration of soluble ionic zinc. The migration data for ionic zinc coming from the substance used in low-density polyethylene as a worst case representative of non-plasticised polymers, comply with the current specific migration limit (SML), but in combination with the dietary exposure from other sources the upper level (UL) of 25 mg/person per day could be exceeded.