Authors describe three cases of agranulocytosis in patients with giant cell (temporal) arterities treated with Dapsone and corticosteroids. The culture in vitro of CFU.GM. cells of two patients, four healthy subject and two patients treated with Dapsone with out granulopenia, demonstrates no any toxic effect of Dapsone. A review of the literature finds 59 cases of agranulocytosis in patients treated with Dapsone alone or in combination with other drugs. Doses of Dapsone ranged from 25 mg to 300 mg a day. Agranulocytosis occurred between the 4th and the 12th week, more often near the 8th week. Agranulocytosis occurred suddenly without previous granulocytopenia. These facts argue for immunoallergic mechanism. This Dapsone side effect requires to restrict its use and to reserve it to serious diseases or failures of other therapeutic drugs. It needs too to keep a close eye on the patients between the 6th and 12th week.