We invite you to join us for the 4th Tri-National Workshop on Standards for Nanotechnology which will take place in Ottawa, Ontario, Canada's National Capital. This two-day workshop will allow researchers from Canada, the United States and Mexico to explore new collaborative research ideas and ways of working together towards harmonized standardization and characterization methods. Lectures will include a variety of research and development topics focusing on measurement and characterization methods supporting toxicological research, health, safety and the environment. The workshop will be arranged along themes consistent with the ISO/TC229 Task Group ‘Measurands for Toxicology Research and Development’, namely: constitution (what is it made of?), appearance (what does it look like?), and factors influencing interactions. Topics will have interest to a broad spectrum of stakeholders involved in nanotechnologies, including academia and government. Invited speakers will be leading researchers from laboratories in Canada, the United States and Mexico.