Hospital readmission is a common way to assess the quality of care provided in an emergency service. In this context, the aim of this study is to quantify and stratify readmissions in a trauma reference emergency service. A retrospective longitudinal study was conducted with patients readmitted, twice or more, in the emergency service within a maximum period of 30 days from the initial admission - hospitalized or not. Clinical and demographic data were obtained from electronic medical records. The readmission rate for the service was 4.11% for all readmissions and 2.23% for avoidable readmissions. Within this group, 61.19% were likely avoidable, 19.47% possibly avoidable, and 19.34% eventually avoidable. Regarding time, 48.16% occurred within one week of the initial readmission. Furthermore, no statistically significant association was found in the analysis of biological sex, occupational accident, and comorbidities. A statistically significant association was found in the analysis of age and ambulance transport (OR 1.37; 95% CI 1.17-1.59). The study highlighted that there are still readmissions in the emergency department that could be avoided. A significant relationship was observed between readmissions and patient ages, and ambulance transport.