Bacterial and fungal infections are the main cause of morbidity and mortality in neutropenic patients. To resolve infections, an adequate number of functional granulocytes is required. Successful treatment of severe infections with granulocyte transfusions is strongly dependent on an adequate number of transfused cells. In this study, 42 neutropenic patients received rhG-CSF-stimulated granulocyte transfusions (GTXs). Of these patients, 18 with severe infections during neutropenia and 8 in a high-risk situation, as defined by severe infections during previous periods of neutropenia or increasing infectious parameters during prolonged neutropenia, received a median of three GTXs (range 1-25), containing a median total of 2.62x10(10) leukocytes (range 0.3-8.61x10(10)). A further 16 patients in a pilot study received prophylactic GTX, consisting of a median of three GTXs (range 1-4) containing a median total of 3.20x10(10) leukocytes (range 0.73-8.51x10(10)). Out of 18 patients with severe infections, 12 improved clinically or showed a resolution of infection after GTX. All 8 patients in a high-risk situation showed a stable clinical course without serious infections. Prophylactic GTX did not result in significant differences with regard to infectious parameters. The median number of transfused platelet units during the course of cytopenia was significantly reduced (13.5 units vs 22.0 units, P<0.02) compared to the control group. For the treatment of infections during neutropenia, rhG-CSF-stimulated granulocyte transfusions are safe and a promising approach.