To assess whether physicians comply with American Society of Clinical Oncology (ASCO) guidelines for the use of CSFs, a prospective survey was performed in 15 Paris university hospitals involved in cancer treatment in 1997. If 45% of the prescriptions complied with the guidelines, primary prophylactic administration, which represented 52% of cases, did not comply with ASCO guidelines. These results suggested that primary prophylactic administration was one major clinical situation in which physicians could benefit from guidance to use a CSFs and that criteria defined by ASCO to allow primary prophylactic administration were not applied in clinical practice.