The University of Iowa Flow Cytometry Facility, established in 1979, was used by 22 departments across four colleges in 2013. Serving this diverse group of investigators requires instruments capable of accommodating a wide range of demands including multi-parameter high-speed cell sorting in a biologically safe manner. The Facility currently operates two cell sorters, a Becton Dickinson (BD) FACS Vantage/DiVa and a FACS Aria II/SORP, both of which are used heavily. There is no question that two cell sorters are necessary to fulfill the obligations of the NIH-funded investigators at this institution. Priorto acquiring the second cell sorter (the FACS Aria II) in 2010, the Facility had a minimum of a one month backlog for sorting experiments. The investigators made it clear that this long waiting period was interfering with their ability to complete their projects and put them at a competitive disadvantage. It is quite clear that this Facility needs two sorters for optimal service delivery. This proposal requests funds for a biologically contained BD FACS Aria SORP cell sorter to replace the BD FACS Vantage/DiVa. While the BD FACS Vantage/DiVa, installed in January 2002, has served as a work horse for a broad range of cell sorting experiments, it has become more difficult to support. BD discontinued sales of the FACS Vantage/DiVa family of instruments in 2007, ended DiVa software upgrades in 2008, and stopped offering service contracts after 2010. The three water-cooled main-frame lasers also require significant maintenance and expense to support. Third party suppliers do not offer Vantage/DiVa parts other than preventative maintenance kits. With parts and support difficult to obtain, there is increased likelihood that an unrecoverable failure that will render the instrument unusable. Moreover, while the Facility's newer BD FACS Aria II/SORP has an aerosol management system and is housed in a biosafety cabinet, the BD FACS Vantage/DiVa only utilizes an aerosol management system for biohazard protection. This has limited the types of samples that can be sorted and thus the projects that can be accommodated with the FACS DiVa. The University of Iowa Flow Cytometry Facility is the sole cell-sorting provider on campus. The only other publicly accessible cell sorter in the state of Iowa is housed at Iowa State University, approximately 130 miles away. The inevitable retirement of the BD FACS Vantage/DiVa will result in a significant adverse impact on the timely completion of the research of numerous investigators if not replaced with a new cell sorter.