The University of Pittsburgh is seeking to renew funding of the Obesity and Nutrition Research Center for its third five-year period. Established in 1992, the initial focus of the Pittsburgh Center was on behavioral interventions. During the current funding cycle, under its new leadership, the Center has retained its focus on clinical investigation, but has substantially expanded its scope to include involvement with metabolic, epidemiological, body composition, genetic and laboratory investigations of obesity and nutrition. At the same time the Center has built upon the prior strength in behavioral interventions for obesity by expanding these endeavors into eating disorders and additional aspects of physical activity and nutrition. Collectively, the goal of the Pittsburgh ONRC is to facilitate and promote research, especially collaborative and multi-disciplinary efforts, to develop more effective interventions for the prevention and treatment of obesity and to gain a more complete understanding of the causes and complications of obesity and other nutritional disorders. This goal is of major public health significance because a majority of adults in this country are overweight or obese, this prevalence is increasing, and the prevalence of obesity in children has increased dramatically during the past two decades. Two of the major complications of obesity are cardiovascular disease and diabetes mellitus, and the research base in these areas is very strong at the University of Pittsburgh. During the past funding cycle, several of the cores have grown significantly. There is now a robust program of body composition, bio-imaging and metabolic research in children and adults, and numerous large epidemiological trials entailing nutritional and activity interventions with vascular disease outcomes. The program and core support for behavioral interventions has also grown substantially, from a few senior investigators into a group of interactive, strongly funded investigators with complementary expertise for whom the presence of the ONRC core facilities has been pivotal. There are several key new initiatives underway including multi-disciplinary programs in childhood obesity and bariatric surgery. Bolstered by strong institutional support, a more diverse scientific base, new facilities, and new partnerships with the adult and pediatric GCRCs, the Pittsburgh ONRC is prepared to continue its important leadership role in clinical research for obesity and nutritional disorders.