The HELENA Project—Healthy Lifestyle in Europe by Nutrition in Adolescence—is a European, collaborative research project financed by the EU Sixth Framework Programme in the area of nutrition-related adolescent health. The basic objective of the HELENA project is to obtain reliable and comparable data from a random sample of European adolescents (boys and girls aged 13–16 years) on a broad battery of relevant nutrition and health-related parameters: dietary intake, food choices and preferences, anthropometry, serum indicators of lipid metabolism and glucose metabolism, vitamin and mineral status, immunological markers, physical activity, fitness and genetic markers. The HELENA project is conceived as a scientific construction with four complementary sub-studies that are elaborated through 14 well-defined work packages. Sub-studies are focused, respectively, on “a cross-sectional description of lifestyles and indicators of nutritional status (HELENA-CSS)”, “a lifestyle education intervention programme (HELENA-LSEI), “a metabolic study with cross-over design (HELENA-COMS)” and a “study on behaviour, food preferences and food development” (HELENA-BEFO). The project unites 20 research centres from 10 European countries. In addition, the consortium comprises five SMEs (small and medium-sized enterprises) that are actively involved in the research activities. The core of the HELENA project study material is an overall European cohort of 3,000 adolescents, equally recruited in ten cities from nine countries. Standardization of methods among partners is a key issue in the project and is obtained through the development of standard protocols, training sessions, validation sub-studies and pilot projects. Health-related problems have a tendency to evolve in cycles, with ever new problems emerging in ever new contexts that call for appropriate and tailored actions. The HELENA project is expected to offer essential elements for use in the overall machinery of required public health nutrition cycles. It is of the greatest importance for its results to prove useful that it can communicate with other initiatives on the level of science and society.