Anaphylaxis is a systemic and hypersensitive allergic reaction caused by various triggers such as environmental, food, drug, and insects. The aim of this study was to identify the prevalence, triggers, and clinical severity of anaphylaxis in 2 emergency departments (EDs) in Saudi Arabia.A cross-sectional study based on a screening of medical records was conducted between January 2015 and August 2017, to identify confirmed cases of anaphylaxis. Patient characteristics were age, sex, previously known allergies, and the triggering allergens. The clinical severity was measured on the basis of the anaphylaxis international assessment tool (mild, moderate, severe). Factors associated with triggers and severities were identified.The period prevalence of anaphylaxis among ED admissions was 0.00026%. Pediatric cases (age 1–16 years) were 98 (60.9%), while adults (age 17–40 years) were 63 (39.1%). Triggers of anaphylaxis were food 63 (39.1%), insects 62 (38.5%), drugs 28 (17.4%), and environmental 8 (5.0%). Mild symptoms were observed in 41 (25%) of the sample, while moderate and severe symptoms were observed in 116 (72%) and 4 (3%) of the cases, respectively. Adults were 1.25 times more likely to endure drug allergy rather than food allergy, than pediatrics with adj.P = .015. ED admissions in summer season were 1.29 less likely to be due to drug allergy rather than insect allergy, compared with admissions in winter season, adj.P = .01. Cases with known allergy were 1.72 times less likely to endure drug allergy rather than food allergy, compared with those with unknown allergy, adj.P = .001. Adults were 4.79 more likely to endure severe symptoms than pediatrics with adj.P = .001.Although the prevalence of anaphylaxis was higher in pediatrics, yet the disease was more severe in adults. Special consideration should be paid to anaphylaxis triggered by insect bites in summer, and food allergy among cases with unknown allergy upon ED admission.