Introduction: Since December 2019, more than 925,000 cases of COVID-19 have been reported worldwide, 8,251 cases in Portugal by the end of March. Previous studies related to the SARS pandemic showed a decrease up to 80% in the emergency care episodes. Hence, the objective of this study is to analyze the use of emergency services during the first pandemic month, compared to historical records. Methods: Data from emergency episodes in mainland Portugal, from January 2014 to March 2020, were downloaded from the National Health Service (NHS) Transparency Portal and the NHS monitoring website. The evolution of emergency services from March to September 2020 was forecasted based on historical data from January 2014 to February 2020. Information for March 2020 was forecasted globally, by the Regional Health Administration (RHA) and Manchester Triage System (MTS). Results: Compared with forecasted values, there was a 48% reduction in the number of emergency episodes in March 2020. In the analysis by the RHA, Alentejo had the smallest decrease in the number of episodes; interestingly, Alentejo is also the area with fewer COVID-19 cases in mainland Portugal. In the analysis by the MTS, the episodes classified as yellow showed the highest reduction (50%). For episodes classified as urgent, there is a difference of about 144,000 episodes during March 2020. Discussion: The results of this preliminary study are aligned with the evidence produced for previous pandemics. Data about the use of emergency services, demographic and clinical characteristics of the episodes would be relevant to analyze this reduction. Conclusion: There was a significant drop in the number of emergency service use in March 2020, and although the causes of this reduction are not determined, the association between the beginning of the pandemic and the reduction of demand is evident. Understanding this phenomenon is crucial to plan interventions to avoid unnecessary morbidities or deaths, caused by a delayed visit to the emergency department.