Hereditary angioedema (HAE) is a rare disease resulting from deficiency of complement 1 esterase inhibitor (C1-INH). The clinical manifestations of this disease include recurrent attacks of self-limiting edema affecting face, extremities, gastrointestinal system and upper airways. In this report, we present eleven members of a family with HAE. Edema of the extremities was the most common symptom, occurring in ten patients. Three patients experienced severe laryngeal edema that required tracheotomy. Three patients developed facial and scrotal edema. Three patients experienced severe abdominal pain. The mean age at onset of symptoms was 11 years. C1-INH levels were undetectable in two patients and low in nine patients. CH50 was undetectable in all of the patients. C4 level for all patients was low. HAE in our first case, a 10-year-old boy, was diagnosed on the basis of low C1-INH, CH50 and C4, in addition to his familial history. Eleven members of this family, for whom laboratory studies could not be done, had similar symptoms and course. Two patients died as a result of laryngeal edema before establishment of dignosis. This case report indicates the importance of recognition and early treatment of HAE to prevent a potentially fatal outcome.