The Clinical Services Core (CSC) is a central resource designed to support each step in the development, conduct, and analysis of all human subject research projects originated from or supported by the Case CFAR. The Core has maintained and expanded a comprehensive and accessible Patient Care and Research Database and linked specimen repository that both facilitates clinical management and serves as a robust resource for research activities. The core provides researchers with access to patients pre-selected for interest and identified as eligible, through the Patient Care and Research Database, to participate in HIV clinical trials or other research studies. It maintains and provides access to a newly established database of over 800 HIV-negative volunteers in the Cleveland area who are interested in participating in HIV research. Assists CFAR researchers in planning and designing studies that use the PCRD and the specimen repository by helping investigators formulate research questions that take full advantage of the data and specimens available through the Core. The Core also coordinates the exchange of clinical and laboratory data with other institutions participating in collaborative projects designed to conduct research on HIV observational data. The Case CFAR is a founding member of two such collaborations, the CFAR Network of Integrated Clinical Systems (CNICS) and the North American AIDS Cohort Collaboration on Research and Design (NAACCORD). Lastly, the Core provides biostatistical and epidemiologic support and advice to Case CFAR investigators, and provides training and faculty development in epidemiology and biostatistics.