This is a resubmission for a new research-training program in Allergy/Immunology at the Massachusetts General Hospital, Harvard Medical School. The goal of this training program is to train MD, MD/PhD and PhD post-doctoral fellows for independent investigative careers in Allergy/Immunology research. Our program will center on our highly successful pre-existing clinical fellowship in Adult and Pediatric Allergy/Immunology and our strong laboratory programs in basic science allergy and immunology research. There have been significant changes in the Allergy/Immunology Unit at the MGH over the last five years with important implications for our training program. After 24 years as Chief of the Allergy/Immunology Unit, Dr. Kurt Bloch retired, and in 2000, Dr. Andrew Luster was appointed Chief of a new Division of Rheumatology, Allergy and Immunology (DRAI) at the MGH. The impetus for this new initiative was to develop a Division within the Department of Medicine that would focus on the immunological and inflammatory basis of human disease. To accomplish this goal, the Center for Immunology and Inflammatory Diseases (CUD) was established, which Dr. Luster directs, as part of the DRAI, to serve as the basic science foundation for the Division. The goal of this Allergy/Immunology training program is to provide supervised laboratory research under the guidance of accomplished faculty members, along with structured training in immunology, molecular biology, genetics and ethical issues through courses and conferences. We have included only outstanding highly accomplished mentors with laboratories at MGH that are actively involved in basic science immunology research. Altogether, eight faculty members participate in this Allergy/Immunology training program as laboratory mentors, and five faculty members participate in the training program as clinical mentors. The participation of these faculty members offers an outstanding training opportunity in Allergy/Immunology research. We believe that we have created a balanced, integrated training program that will offer high quality training in laboratory science research in Allergy/Immunology that successfully integrates both MD and PhD trainees and basic science and clinical faculty. A T32 training program would have a dramatic effect on the Allergy/Immunology program at MGH and is critical to complete the transformation of this program from an excellent clinical program to a program that will produce the next generation of physician-scientists and PhD scientists committed to Allergy/Immunology research.