The incidence of community-acquired pneumonia (CAP) ranges from 2-15 cases/1,000 inhabitants/year, being higher in those over 65 or in patients with comorbidities. In Emergency Room (ER) it represents up to 1.35% of the care. Approximately 75% of all diagnosed CAPs are treated in ER. The CAP represents the origin of the majority of septic sepsis and shock diagnosed in ER, the leading cause of death and admission to the intensive care unit (ICU) for infectious disease. A global mortality of 10-14% is attributed according to age and associated risk factors. 40-60% of CAPs will require hospital admission, including observation areas (with very variable ranges of 22-65% according to centers, time of year and patient characteristics), and between them 2-10% will be in the ICU. From all that has been said, the importance of CAP in ER is translated, and also of the “impact of emergency care on patients with CAP”, as it is the device where initial, but fundamental, decisions are made for evolution of process. The great variability among clinicians in the management of diagnostic-therapeutic aspects in the CAP is known, which is one of the reasons that explain the large differences in admission rates, of achieving the microbiological diagnosis, request for complementary studies, the choice of antimicrobial regime or the diversity of care applied. In this sense, the implementation of clinical practice guidelines with the use of prognostic severity scales and the new tools available in HUSs such as biomarkers can improve the care of patients with CAP in ER. Therefore, based on a multidisciplinary group of emergency professionals and specialists participating in the CAP care process, this clinical guide has been designed with various recommendations for decisions and key moments in the process of patient care with NAC in the Emergency Room.