Increasing age is not, in itself, a contraindication to cancer chemotherapy. Myelosuppression, however, a common adverse consequence of the administration of many standard-dose chemotherapy regimens to both young and elderly patients with cancer, increases with age. The risk of development of febrile neutropenia may contribute to a reluctance to administer chemotherapy in the elderly patient population. We conducted a detailed literature search (1992-2002) to derive evidence-based conclusions on the value of prophylactic colony-stimulating factor (CSF) administration in elderly patients receiving chemotherapy. Sufficient evidence allows us to affirm that prophylactic granulocyte colony-stimulating factor (G-CSF) reduces the incidence of chemotherapy-induced neutropenia, febrile neutropenia and infections in elderly patients receiving myelotoxic chemotherapy for non-Hodgkin's lymphoma (NHL), small-cell lung cancer (SCLC) or urothelial tumours. Lack of available trial data does not allow similar conclusions to be drawn for other cancers studied, but it is likely that similar benefits would accrue from the use of prophylactic G-CSF. There is insufficient evidence to extend this recommendation to include the use of granulocyte-macrophage colony-stimulating factor (GM-CSF). There are insufficient data available to allow the evaluation of the impact of prophylactic CSF on the incidence of toxic deaths in elderly patients with cancer and this is a crucial question for geriatric oncology practice. There is no evidence in elderly patients that the delivery of standard-dose chemotherapy on schedule improves efficacy measures. The data show that febrile neutropenic events are more likely to occur during the first and second cycles of chemotherapy, thus prophylactic measures should be considered early in the course of treatment. Furthermore, since systematic dose reduction can impact on outcome, primary prophylactic use of G-CSF for all elderly patients receiving curative myelotoxic chemotherapy (cyclophosphamide, doxorubicin, vincristine and prednisolone (CHOP) or CHOP-like) is indicated and we suggest a risk-adapted strategy with primary prophylactic G-CSF administration in high-risk patients. Dose intensification, through dose interval reduction, facilitated by prophylactic G-CSF, improved survival in elderly patients with some specific diseases. There is a need for further well-designed studies to identify the elderly patients who will benefit most from prophylactic G-CSF. To achieve this, we strongly urge the design of and participation in further trials.