Summary We propose to establish the National Center for In-situ Tomographic Ultramicroscopy (NCITU) to be based at the Simons Electron Microscopy Center (SEMC), which is a part of the New York Structural Biology Center (NYSBC), based in New York, NY. NCITU is dedicated to developing and providing access to both standard and advanced methods for in-situ cryoET specimen preparation, and to disseminating this expertise through a cryoET cross-training program designed to serve a wide variety of skill levels and career goals. The primary goal of the National Center for In-situ Tomographic Ultramicroscopy (NCITU) is to provide user access and service towards preparing specimen for direct visualization of macromolecular associations and organization, particularly in native cells. A highly qualified technical team provides direct hands-on service, guidance, and assistance to ensure that samples and grids are prepared with the highest quality and in the shortest time possible. An already well established cross-training program is being expanded and extended to provide training in every aspect of the cryoET specimen preparation pipeline. This is a request for supplemental funding for the National Center for In-situ Tomographic Ultramicroscopy (NCITU) to enhance the quality and throughput of the TFS Aquilos 2 cryo-FIB-SEM. This is a specific request for (i) a high-vacuum sample transfer rod, (ii) an in-chamber water vapor reduction upgrade, and (iii) a liquid nitrogen cooling longevity upgrade.