Nutrition during childhood and adolescence is an important determinant of development and health, both for the child and the later adult. In industrialised countries as well as in many countries of economic transition, emphasis has moved from combating nutrient deficiencies to research on the effects of overnutrition and food selection. Prevention of chronic diseases including obesity have become a major focus in research. However, the complex relation between infant growth and its related endocrine and metabolic changes on the one hand and the influence of nutrition and nutritional status on the other hand still need to be understood in detail. Studies aiming to elucidate this have to follow children and adolescents during their growth period. The following pages display the features of the German DONALD Study ( DOrtmund Nutritional and Anthropometric Longitudinally Designed Study) which was specifically designed to address these complex research questions. Finally, comparisons to other studies are made and the specific strength and weaknesses of this study are discussed. As the DONALD study offers unique research opportunities and due to its long follow-up an abundance of data, collaborative research is encouraged.