The promise and challenge of nanotechnology is immense. The National Nanotechnology Initiative provides an opportunity to develop a new technological base for U.S. Industry. Nanometrology is the basis of the new measurement methods that must be developed to support the nanotechnology. Nanometrology has played a key role in support for the semiconductor and other U.S. industries already developing products with nanometer-sized dimensions. Nanometrology techniques, standards and infrastructure development are needed to control fabrication and production, ensure product quality, and enable different parts to work effectively together. Size and tolerance are important considerations and require standardization. Metrology is critical to developing a complete understanding of any new phenomenon or process. Only those things that can be measured can be fully understood. Ultimately, this understanding is critical to obtaining the immense economic benefits predicted by the National Nanotechnology Initiative for U. S. industry.