High dose chemotherapy and autologous bone marrow transplantation (BMT) can produce prolonged remission in patients with malignant lymphoma or solid tumours. However, neutropenia is a serious complication of treatment in patients with these diseases. In this study, we investigated the costs and effects of using lenograstim, a recombinant human granulocyte colony-stimulating factor, to treat neutropenia in 16 patients with lymphoma or solid tumours. The cost of lenograstim was not included in the calculations. The duration of neutropenia and hospitalisation were both lower in patients who received lenograstim compared with no treatment. The mean cost of autologous BMT was FF142,000 in patients who received lenograstim, compared with FF166,000 in patients who did not. Savings were largely attributable to decreased expenditure on hospitalisation in the lenograstim-treated group. The cost of 14 days' treatment with lenograstim was estimated at FF10,500, based on a daily dosage of 150 micrograms/m2/day.