Objective To investigate the documentation of sepsis and a sense of urgency throughout the acute care chain. Design Prospective cohort study. Setting Emergency department (ED) in a large district hospital in Heerlen, The Netherlands. Participants Participants included patients ≥18 years with suspected sepsis who visited the ED during out-of-hours between September 2017 and January 2018 (n=339) and had been referred by a general practitioner and/or transported by ambulance. We defined suspected sepsis as suspected or proven infection and the presence of ≥2 quick Sepsis-related Organ Failure Assessment and/or ≥2 Systemic Inflammatory Response Syndrome criteria. Outcome measures We analysed how often sepsis and a sense of urgency were documented in the prehospital and ED medical records. A sense of urgency was considered documented when a medical record suggested the need of immediate assessment by a physician in the ED. We described documentation patterns throughout the acute care chain and investigated whether documentation of sepsis or a sense of urgency is associated with adverse outcomes (intensive care admission/30-day all-cause mortality). Results Sepsis was documented in 16.8% of medical records and a sense of urgency in 22.4%. In 4.1% and 7.7%, respectively, sepsis and a sense of urgency were documented by all involved professionals. In patients with an adverse outcome, sepsis was documented more often in the ED than in patients without an adverse outcome (47.9% vs 13.7%, p<0.001). Conclusions Our study shows that in prehospital and ED medical records, sepsis and a sense of urgency are documented in one out of five patients. In only 1 out of 20 patients sepsis or a sense of urgency is documented by all involved professionals. It is possible that poor documentation causes harm, due to delayed diagnosis or treatment. Hence, it could be important to raise awareness among professionals regarding the importance of their documentation.