A case of fatal agranulocytosis in an adolescent who was on carbamazepine therapy is presented. The clinical and laboratory findings suggest that the primary cause of the disorder was neutropenia rather than infection, and the preceding factor for neutropenia was carbamazepine. The timing of occurrence of the hematologic picture, its dependency on dose increments, and the lack of symptoms until infection supervened are consistent with an idiosyncratic-toxic drug reaction (type 2 drug reaction). This is the first reported agranulocytosis case due to crabamazepine in adolescence.