Background: Hereditary angioedema (HAE) is a rare auto-somal dominant disorder characterized by C1-INH (C1 esterase inhibitor), low serum levels (type I), dysfunction (type II) or normal serum levels and function (type III), which lead to subcutaneous and submucosal edema attacks. The aim of this study was to investigate the demographic, clinical and laboratory findings of Iranian patients with HAE. Methods: The patients with a history or symptoms of angioedema who were referred to Immunology, Asthma and Allergy Research Institute (IAARI) between Jan 2006 and Jan 2014, were assessed based on a specific questionnaire and laboratory evaluation. The patients " with a definite diagnosis of HAE type I and type II were entered into this study. Results: Among 51 patients, 63.3% were diagnosed with HAE type I and 36.7% with HAE type II. Fifteen patients were under 18 years and 36 were adults. The mean age of symptoms onset and diagnosis were 12.33 +/- 10.20 years and 24.48 +/- 14.64 years, respectively. The mean delay of diagnosis was 11.02 +/- 11.60 years. The most commonly involved locations of edema were hands, face and genitalia. Moreover, laryngeal edema was observed in 61.2% of patients, which led to death in two patients during this study. Conclusion: Hereditary angioedema is a life threatening disease with considerable morbidity and mortality. The outcomes of this-study can be used to inform clinicians and health care providers about HAE, which can help earlier diagnosis and better management of the patients, specifically in life threatening attacks.