Climate change is already having serious impacts on the safety and health of workers in all regions of the world. Workers are among those most exposed to climate change hazards yet frequently have no choice but to continue working, even if conditions are dangerous. Global occupational safety and health (OSH) protections have struggled to keep up with the evolving risks from climate change, resulting in worker mortality and morbidity. The report “Ensuring safety and health at work in a changing climate" presents critical evidence related to six key impacts of climate change on OSH, which were chosen for their severity and the magnitude of their effects on workers: excessive heat, ultraviolet (UV) radiation, extreme weather events, workplace air pollution, vector-borne diseases and changes in agrochemical use. It includes the most pertinent evidence regarding worker exposures and the main safety and health impacts. It also summarizes examples of existing responses to these hazards, such as policies and strategies, laws, collective agreements, technical guidelines, training and advisory initiatives, awareness raising campaigns and workplace level actions.