Background: Hereditary angioedema (HAE) is a rare autosomal dominant primary immunodeficiency with complement system defect characterized by recurrent episodes of angioedema involving the skin or mucosa of the upper respiratory and gastrointestinal tracts. Objective: To characterize the clinical and laboratory data of hereditary angioedema in Iran. Methods: Patients with probable diagnosis of angioedema were enrolled in this study. Demographic and clinical data were documented in the designed questionnaire including history of attacks, triggering factors and laboratory data such as C4, C1 esterase inhibitor level and function. Results: Among 63 patients who were clinically suspicious for angioedema (23 males and 40 females), 8 cases (12.7%) were diagnosed with HAE. Among these 8 HAE patients, 3 were diagnosed with HAE type 1 and five patients were diagnosed with HAE type 2. The mean ages of HAE type 1 and type 2 patients were 25.6 +/- 13.5 and 22.4 +/- 12.32 years. The mean age of onset in HAE type 1 group was 8 +/- 5 years and in HAE type 2 group was 18.8 +/- 11.84 years. The mean diagnosis delay was 17.6 years in HAE type 1 patients and 2.6 years in HAE type 2. The most common clinical manifestation was facial swelling presented in all HAE patients followed by swelling of extremities which was present in 7 patients with HAE. Conclusion: The clinical criteria of the Iranian patients with HAE were consistent with the known clinical patterns of the disease.