The National Institute for Occupational Safety and Health through its Nanotechnology Research Center has developed a Strategic Plan for Nanotechnology Safety and Health Research. This Strategic Plan identified knowledge gaps and critical issues, which must be addressed to protect the health and safety of workers producing nanoparticles as well as those incorporating nanoparticles into commercial products or using nanomaterials in novel applications. This manuscript lists the projects that comprise the Nanotoxicology Program in NIOSH and provides a brief description of the goals and accomplishments of these projects.