A series of activities were undertaken to understand the underrepresentation of people with disabilities in science, technology, engineering, and mathematics (STEM) careers and increase their participation in these fields. "AccessSTEM" collaborated with key stakeholders to conduct a "Capacity-Building Institute" ("CBI") in April 2009; share results of the CBI with National Science Foundation (NSF) projects and other stakeholders; provide an electronic forum to continue discussion of accessibility issues and provide support for accessibility efforts; and extend resources to other programs and promising practices via an online searchable Knowledge Base. The "AccessSTEM Capacity Building Institute" took place April 27, 2009, in Seattle. Its overall purpose was to explore ways to increase the participation of people with disabilities in all science, technology, engineering, and mathematics (STEM) projects, academic programs, and, ultimately, careers. A particular focus was on potential interventions for high schools, community colleges, and two-year schools in and near Seattle. The goal of the AccessSTEM CBI was to share AccessSTEM project objectives and progress and to brainstorm ideas for future collaborations and activities. Broad issue areas discussed included: (1) barriers to STEM for students with disabilities; (2) lessons learned in previous DO-IT (Disabilities, Opportunities, Internetworking, and Technology) projects; and (3) results from DO-IT's longitudinal transition study (ALTS). The "CBI" Agenda, presentation summary, reports from small group discussion, list of "CBI" participants, and information relating to the "AccessSTEM" Web site and searchable knowledge base are included.