Background: Twenty percent of all newly diagnosed patients with small-cell lung cancer (SCLC) are > 75 years. Elderly patients may show more toxicity due to co-morbidity. We evaluated motives for adherence to treatment guidelines, completion of treatment and toxicity. Patients and methods: Population-based data from patients aged >= 75 years and diagnosed with SCLC in 1997-2004 in The Netherlands were used (368 limited disease and 577 extensive disease). Additional data on co-morbidity (Adult Co-morbidity Evaluation 27), World Health Organisation performance status (PS), treatment, motive for no chemotherapy, adaptations and underlying motive and grade 3 or 4 toxicity were gathered from the medical records. Results: Forty-eight percent did not receive chemotherapy. The most common motives were refusal by the patient or family, short life expectancy or a combination of high age, co-morbidity and poor PS. Although only relatively fit elderly were selected for chemotherapy, 60%-75% developed serious toxicity, and two-thirds of all patients could not complete the full chemotherapy. Conclusions: We hypothesise that a better selection by proper geriatric assessments is needed to achieve a more favourable balance between benefit and harm.