Objectives Effects of nanoparticles including zinc oxide nanoparticles, titanium oxidenanoparticles, and their mixtures on skin corrosion and irritation were investigated byusing in vitro 3D human skin models (KeraSkinTM) and the results were compared tothose of an in vivo animal test. Methods Skin models were incubated with nanoparticles for a definite time period andcell viability was measured by the 3-(4, 5-dimethylthiazol-2-yl)-2.5-diphenyltetrazoliumbromide method. Skin corrosion and irritation were identified by the decreased viabilitybased on the pre-determined threshold. Results Cell viability after exposure to nanomaterial was not decreased to the pre-determinedthreshold level, which was 15% after 60 minutes exposure in corrosion test and50% after 45 minutes exposure in the irritation test. IL-1α release and histopathologicalfindings support the results of cell viability test. In vivo test using rabbits also showednon-corrosive and non-irritant results. Conclusions The findings provide the evidence that zinc oxide nanoparticles, titaniumoxide nanoparticles and their mixture are ‘non corrosive’ and ‘non-irritant’ to the humanskin by a globally harmonized classification system. In vivo test using animals can be replacedby an alternative in vitro test.