A variety of cooperative relationships may potentially exist between professional or voluntary organizations and food companies: endorsements of food products, health messages, or educational and informational materials; certification of nutrient components of food products that meet a certain standard of a society; and acceptance of food advertising in society publications and the display of food products at society meetings. We queried the American Heart Association, the Society for Nutrition Education, the American Cancer Society, the American Diabetes Association, and the American Dietetic Association about past and present policies on these various relationships. Specific examples of cooperative relationships are discussed, weighing risks and benefits to the food company, the professional or voluntary organization, and the public. Guidelines are suggested for professional societies in evaluating different cooperative relationships, with the public's health and nutritional well-being as the primary consideration.