Many major biomedical research problems are best addressed using a multi-disciplinary approach that extends beyond the traditional biological and clinical sciences. Principles and techniques in allied quantitative sciences such as physics, mathematics, chemistry, computer sciences, and engineering are increasingly being applied to good effect in biomedical research. Bioengineering integrates principles from a diversity of technical and biomedical fields, and the resulting multi-disciplinary research is providing new basic understandings, novel products, and innovative technologies that improve basic knowledge, human health, and quality of life. Bioengineering also crosses the boundaries of scientific disciplines that are represented throughout academia, Federal laboratories, and industry. Recognizing the importance of bioengineering in public health, the Bioengineering Consortium (BECON; http://www.becon.nih.gov) was established in 1997 as a focus for bioengineering activities at the NIH. Solicited here, under the auspices of BECON, are grant applications that propose bioengineering research projects that serve the mission of one or more of the participating NIH institutes or centers.