World Health Organization has developed these guidelines with recommendations on how best to protect workers from the potential risks of manufactured nanomaterials (MNMs). The recommendations are intended to help policy-makers and professionals in the field of occupational health and safety in making decisions about the best protection against potential risks specific to MNMs in workplaces. These guidelines are also intended to support workers and employers. However, they are not intended as a handbook or manual for safe handling of MNMs in the workplace because this requires addressing more general occupational hygiene issues beyond the scope of these guidelines. The publication includes executive summary in Arabic, Chinese, French, Russian and Spanish.