We evaluated granulocyte colony-stimulating factor (G-CSF) as an adjunct to courses of conventional chemotherapy in 16 children with cancer. One course followed by G-CSF (20 episodes) was compared to identical courses without G-CSF (20 episodes) in the same patients. The mean duration of G-CSF therapy was 8.8 (5-13) days. The periods of neutropenia (4.8 days versus 16.5 days; p < 0.0001), days of hospitalization for febrile neutropenia (13 days versus 65 days; p = 0.02) and days on broad-spectrum antibiotics (13 days versus 95 days; p = 0.003) were significantly reduced. With the use of G-CSF the profound neutropenia could be prevented in 11 (55%) episodes. There were two episodes of fever and neutropenia in the G-CSF group as compared to 10 febrile neutropenias in the control group (p = 0.04). G-CSF was well tolerated and did not cause additional expenses when compared to the expenses needed for the treatment of febrile neutropenias. The cost benefit analyses showed that through using G-CSF a savings was realized in the amount of U.S. $20,650 for 20 cycles of chemotherapy, i.e., U.S. $1,033/chemotherapy cycle. We conclude that the use of G-CSF was efficacious and did not increase the total costs of therapy.