This program prepares scientists for research careers in the computational and mathematical modeling of medically significant biological systems through interdisciplinary training at the predoctoral level. Noted for its well-established system of interdisciplinary graduate programs and for its tradition of collaborations across departmental boundaries, the University of Arizona provides a highly suitable environment for such training. Fifteen training faculty with appointments in multiple departments and interdisciplinary graduate programs provide strength in five broad areas: bioinformatics; molecular dynamics; cellular processes; physiology and pathophysiology; biostatistics and stochastic processes. Students will be drawn from multiple graduate programs in mathematical and life sciences, including the programs in Applied Mathematics and in Biochemistry and Molecular & Cellular Biology. In most cases, students will receive two years of support from this program, starting in their second or third year of graduate training. Trainees will pursue the coursework requirements of their own graduate programs and, in addition, take graduate courses in mathematical modeling and in bioinformatics, which are tailored to the trainees' needs and take into account their diverse scientific backgrounds. All trainees will take part in a weekly Quantitative Biology Colloquium that has been running continuously for more than twenty years. This colloquium includes presentations by students, faculty and visiting speakers, and promotes dialog between trainees and faculty with primarily mathematical or computational backgrounds and those with strong biological training. It will include components explicitly devoted to training in responsible conduct of research, methods for enhancing reproducibility, and career development including preparation for a range of careers in biomedical research. Trainees will carry out their doctoral research with advisors whose research, whether theoretical or experimental, emphasizes application of theoretical approaches to biomedical problems. Trainees participating in this program will not only receive research training in relevant areas, but, equally importantly, will develop the ability to communicate and collaborate across traditional disciplinary boundaries and to work with researchers with complementary expertise. Researchers with such skills are critically needed in many areas of biomedical science in which sophisticated theoretical approaches are necessary in order to achieve further progress.