Flow Cytometry is an important analytical and cell purification tool in cancer and immunological research. Modern cancer analysis requires innovative procedures that include both imaging methods and non-imaging analysis, such as that provided by flow cytometry. Flow cytometry allows the isolation of pure cell populations comprising less than 0.01% of a complex mixture. In addition, as an analytical tool it permits statistical analysis of cell population and cell function changes, apoptosis, intracellular protein expression, and gene transfection for example. Innovative methods that contribute to modern cancer research include gene expression detection with green fluorescent protein, parameter cytometry, apoptotic effect of chemotherapy, multi-drug resistance evaluation, and minimal residual disease detection. In addition, the integrated use of cell isolation (by flow cytometry) and downstream assessment of isolated cells (by proteomics or genomics) offers a powerful application of technologies offered by multiple Resources within the Knight Cancer Institute. High quality instrumentation is available to Knight Cancer Institute members in the form of two cell sorters and three analytical instruments. The Flow Cytometry Shared Resource provides consultation, training/teaching, technical expertise, and technical services in flow cytometry to meet the needs of Knight Cancer Institute members.