The report reviews the applicability of the Globally Harmonised System of Classification and Labelling of Chemicals (GHS) hazard classification criteria to manufactured nanomaterials considering the recent data generated and compiled in the nanomaterial testing program under the OECD Working Party on Manufactured Nanomaterials. In addition, data from the EU NANoREG project, the EU NanoSafety Cluster projects, REACH registrations and publicly available literature were used. The project focused on four nanomaterials and selected health hazard classes. The available test data were evaluated with respect to applicability of the test methods, applicability of the GHS criteria, identified data gaps and uncertainties and need for revision of GHS criteria or guidance. The report also highlights specific issues to be considered when classifying nanomaterials.