The interest on developing public health policy interventions to reduce obesity and improve nutrition in last decades has progressively grown as a response to increasing overweight and obesity prevalence. ELANS (Estudio Latinoamericano de Nutricion y Salud) or Latin America Study on Nutrition and Health, is a household-based multi-national cross-sectional survey whose aim is to describe the nutritional status of the Latin-American people, and investigate food and nutrients intake as well as physical activity status of nationally representative samples from urban populations. This study evaluated with an unique methodology, a randomized sample with 9218 people (15-65y) in 8 countries simultaneously (Argentina, Brazil, Chile, Colombia, Costa Rica, Ecuador, Peru and Venezuela). Many challenges and barriers to conduct this study arose at the very beginning: the complexity of the selection of team members, communications, inclusion of technical scientific advisors. The requirement of having a common protocol with the same set of data collection tools, involved 15 months of collaborative work. In addition, obtaining ethical approval from 8 different boards plus a centralized external Institutional Review Board (IRB) at a similar range of time became an extra challenge. A Contract Research Organization (CRO), was responsible for the recruitment and data collection. To ensure the feasibility, efficiency and adherence to the study protocol and procedures a pilot study was crucial. A simultaneous fieldwork, under standardized and uniformed conditions of application of questionnaires and measurements required a continuous and exhaustive work from the Coordination Center consisted in two chairs, one co-chair and two project managers. A tight collaboration with each academic/research team was performed. During the fieldwork periodical controls of data quality were carried out and a general consistency after completion of data collection was developed. Specifically, the dietary intake consistency was the most complex: technical support and guidance to all research teams were necessary. From ELANS many lessons were learned regarding the conduction and coordination of a multicenter study: 1- the inclusion of a multidisciplinary team with deep knowledge in specific areas was essential, 2-the key role of a proactive supervision and coordination of an international team allowed the simultaneous developed of the study at every country, 3- designing and following a feasible and realistic protocol required more effort than expected, 4- the value of taking care of local characteristics of each site at the moment of planning and developing the fieldwork allowed to identify and solve local barriers 5- the communication with the CRO and the supervision of its work was critical to ensure data quality. These are a tiny example of many other learnings achieved. The findings of this study will provide scientific information on nutrition and physical activity, and due to strict procedures of data quality control allowing the comparison between the LA countries. It is also a good example of a multi center collaboration study that contributes with learnings and tools for other research teams.