For the first time in a clinical study oral Ifosfamide was used: 65 elderly or unfit patients with small cell lung cancer (SCLC) were treated as outpatients with fractionated oral Ifosfamide and Etoposide. Forty patients (62%) had extensive stage (ED) disease. The median age of the patients was 66 years. In the 60 patients evaluable for response the objective response rate was 90% with a complete response (CR) rate of 32% and a partial response (PR) rate of 58%. The overall median survival of all 65 patients was 11 months (13 months for LD, 9.5 months for ED). In those patients with LD achieving a CR or a PR radiotherapy was given to the mediastinum. No prophylactic cranial irradiation was given. There was a rapid improvement in the responding patients' performance status and symptoms generally with the first treatment cycle. Overall haematological toxicity was mild, with intravenous antibiotics only being required in 4% of the courses and with only one treatment-related death from septicaemia. A higher than expected rate of CNS toxicity was seen (30%). This was generally mild and always fully reversible and consisted mainly of forgetfulness, occasionally hallucinations, nightmares and somnolence. In only one case did encephalopathy necessitate early termination of treatment. This raises the question of whether Ifosfamide metabolism differs quantitatively or qualitatively when given by the oral route as opposed to the usual intravenous route. We conclude that this simple outpatient based treatment gives a high response rate with rapid improvement in symptoms.