This article describes the economic and social impact of neutropenia induced by myelotoxic chemotherapy in patients with cancer during the period 1 January-31 December 1991. Neutropenia is a life-threatening complication of chemotherapy in patients with cancer. The episodes of fever and infections originating from neutropenia require hospitalization of the patient until the granulocyte levels are restored. The calculation of the economic cost was based on the following parameters: length of stay in hospital, analytical tests performed on the patient, type and cost of drug therapy administered, blood transfusions performed, health assistance received, cost of isolation and absence from work. The overall economic cost of neutropenia in patients with cancer reached 329,775 pesetas ($2,893). Cost of the health-care staff was the largest budget item in relation to the total health resources estimated.