Recent successes in the isolation, identification, and characterization of totipotent, pluripotent, or multipotent stem cells derived from embryonic, fetal, and adult sources have fueled an enthusiasm for development of novel, cell-based therapeutic strategies for treating a broad array of disease conditions. The Food and Drug Administration (FDA) recognizes that therapies based on stem cell technology may hold unprecedented potential. Among many conditions for which this class of products might be considered, serious disorders of the nervous system are prominent. Available preclinical data appear to provide a rationale for the use of cellular replacement therapies in several central nervous system indications, including Parkinson disease, stroke, and spinal cord injury. Efficacious conventional treatments for these diseases or conditions are often nonexistent or unsatisfactory. Existing evidence suggests that certain types of pluripotential cells delivered to the central nervous system are responsive to signals elicited by the local physiological environment. Consequently, implanted stem cells are influenced to adopt characteristics that are appropriate for producing a desired clinical effect. On the basis of these findings and in conjunction with the results projected to be obtained from ongoing basic research efforts, the FDA anticipates that initial human safety studies involving delivery of stem cells to patients with serious, debilitating diseases or conditions of the central nervous system are likely to be proposed in the near future. To obtain the best scientific and medical guidance available for facilitating formulation of appropriate regulatory decisions relating to cellular replacement therapies, the FDA convened a meeting of its Biological Response Modifiers Advisory Committee. Augmented by prominent basis and clinical research scientists with expertise in stem cell biology and treatment of neurologic disorders or diseases, the advisory committee meeting provided a forum for identifying novel and significant issues that must be considered to evaluate the risks and benefits of stem cell therapeutic approaches intelligently. This presentation will serve to highlight and summarize the advisory committee recommendations.