A young woman with glycogen storage disease, type Ib, and chronic neutropenia had severe recurrent infections. In a life-threatening situation, treatment with granulocyte colony-stimulating factor (G-CSF) resulted in the prompt correction of neutropenia. Subsequently, daily G-CSF therapy has allowed the maintenance of a normal neutrophil count and marked clinical improvement over a period of 18 months. The spectrum of neutropenic conditions which are responsive to G-CSF should include this inherited metabolic disorder.