Idiopathic thrombocytopenic purpura (ITP)-like syndrome is a rare complication of carcinomas, and its treatment usually precedes cancer therapy in order to make further procedures safe. We describe the case of a 78-year-old man with a small-cell lung cancer of extended stage, associated with ITP-like syndrome, which proved resistant to treatment with corticosteroids and vincristine, short-responsive to IV immunoglobulin, but quickly and steadily responsive to low-dose interferon (ld IFN, 3 million IU, sc, twice weekly, for 8 weeks), until the patient's death, due to his primarily chemoresistant cancer. This case is, to our knowledge, the second reported ITP-like syndrome in a cancer patient who had been successfully treated with ld IFN. The excellent and cost-effective therapeutic index of ld IFN makes it an attractive alternative treatment in patients with this specific complication and calls for further investigation regarding its potential use as a first-line treatment. Am.