Japan’s National Institute of Advanced Industrial Science and Technology (AIST) announced in October 2013 a voluntary guidance document on measuring airborne carbon nanotubes (CNT) in workplaces. The Technology Research Association for Single Wall CNTs (TASC), a consortium of nine companies and AIST, prepared the guidance, which is intended to provide a means of CNT safety management. The guidance summarizes the available practical methods for measuring airborne CNTs: (1) on-line aerosol measurement; (2) off-line quantitative analysis (e.g., thermal carbon analysis); and (3) sample collection for electron microscope observation. The guidance also presents measurement cases performed by TASC. TASC developed the guidance under the project “Innovative carbon nanotubes composite materials project toward achieving a low-carbon society,” which is sponsored by the New Energy and Industrial Technology Development Organization (NEDO). The guidance notes that a specific method has not yet been definitively determined, and many challenges still remain.