Brazil is back on the hunger map, with approximately 33 million Brazilians suffering food insecurity. Chronic malnutrition affects some 12.4% of the country’s poorest children, and adverse climate conditions further hinder the situation’s containment. Global warming has altered the rainfall patterns in all regions of Brazil, leading to an increase in the incidence of extreme precipitation events such as droughts and floods. This project’s objective is thus to study the impact of extreme climate events related to precipitation (such as droughts and floods) and thermal exposure (including heat, heat waves, and thermal stress) on maternal and child nutrition outcomes in different ecological contexts and population groups. The study is based on the hypothesis that extreme temperatures can directly impact a child’s capacity to retain available nutrients due to the loss of appetite induced by thermal stress and to the increase in dehydration or to the elevated risk of diarrhea, resulting in malabsorption of nutrients and calories and acute undernutrition, leading in turn to weight loss. In addition, prolonged restrictions of these aspects can lead to chronic malnutrition and stunting, leaving children susceptible to infectious diseases such as malaria, respiratory tract infections, and intestinal infections, ultimately contributing to increased mortality. The project will use the robust ecosystem of Brazilian administrative data linked to CIDACS, considering the 100 Million Brazilian Cohort and Live Birth Cohorts, as well as its Climate and Health Data Platform. The integration of these powerful and longitudinally representative national resources will allow understanding and providing evidence to support the adoption of adaptative actions, increasing health services’ resilience and mitigating climate changes’ effects on the health of maternal and child populations in the short and long term, especially for the most vulnerable groups. This approach will facilitate a more effective journey for achieving the Sustainable Development Goals (SDGs).