We report on a 37-year-old female patient with generalised giant-cell tumour of the bone, whose tumour was refractory to conventional chemotherapy. Subsequent treatment with interferon alpha 2a in increasing dosage from 4 x 10(6) IU (three times a week) to 9 x 10(6) IU (three times a week) led to a significant decrease of pulmonary metastases and a stabilisation of the disease after 12 months of treatment. In progressive chemotherapy refractory giant-cell tumour interferon alpha 2a may be of therapeutic benefit.