Introduction: Emergency medical services (EMS) have the opportunity to treat allergic reactions anaphylactic reactions rapidly. However, the rate of recognition and treatment is unknown. Methods: This was a retrospective cohort study conducted at two urban emergency departments from 2007 to 2012 including adult patients with allergy and anaphylaxis, both of which were predefined by explicit criteria. The patients of interest were those attended by EMS and transported to hospital. The primary outcome was the proportion of patients who met anaphylaxis criteria in the prehospital setting, but who did not have epinephrine administered. The secondary outcome was the proportion of patients who did not meet anaphylaxis criteria, yet had epinephrine administered. Results: Of 2819 overall patients, 491 (17.4%) arrived by EMS. The median age was 38 (IQR 27 to 49) and 60.9% were female. For the 151 (30.8%) patients with anaphylaxis, 55 received ephinephrine, (36.4%, 95% CI 27.4 to 47.4%). For the 340 (69.2%) patients without anaphylaxis, 28 received ephinephrine (8.2%, 95% CI 5.5 to 11.9%). Conclusion: For patients with anaphylaxis and allergic reactions who are managed by EMS, there may be a mismatch between illness severity and treatment.