Background: Up to 1/3 of LS SCLC patients are cured by chemoradiotherapy (CRT), but severe toxicity is frequent and population-based studies show that many patients do not receive standard CRT. More knowledge on how to predict who experiences side-effects or achieves long term disease control is needed. Poor nutritional status is strongly associated with inferior survival in many types of cancer including non-small cell lung cancer, but little is known about whether this is the case in LS SCLC. We investigated whether nutritional status reported by patients on the Patient-Generated Subjective Global Assessment Short Form (PG-SGA SF) was associated with toxicity and survival among participants in a trial comparing high dose with standard dose twice-daily TRT in LS-SCLC (NCT02041845, n=170). Methods: Patients received four courses of platinum/etoposide chemotherapy and were randomized to TRT of 60 Gy/40 fractions or 45 Gy/30 fractions. Patients completed PG-SGA SF before treatment commenced and were categorized as having low (PG-SGA SF score 0–3.9), intermediate (4.0–8.9) and high (≥9) risk of malnutrition. Toxicity was graded according to CTCAE 4.0. Median follow-up for survival was 49 months. Results: 113/170 (66.5%) patients completed PG-SGA SF at baseline. Median age was 65 years, 46.0% were men, 88.5% had PS 0-1, 87.6% stage III disease and 22.1% weight loss of >5% the three months before inclusion. Median PG-SGA SF score was 3.0, 52.2% of patients had low, 29.2% intermediate, and 18.6% high risk of malnutrition. Numerically, there were more patients with stage III, PS 1-2 and pleural fluid among those at high risk. There was no difference in mean no. of chemotherapy courses (low: 3.85, intermediate: 3.88, high: 3.90, p=0.95) or TRT completion (low: 96.6%, intermediate: 97.0%, high: 95.2%, p=1.0). There were no statistically significant differences in proportions who experienced grade 3-4 toxicity (low: 88%, intermediate: 91%, high: 86%, p=0.86), median PFS (low: 15.1 months, intermediate: 11.8 months, high: NR, p=0.23), 2-year survival (low: 68%, intermediate: 52%, high: 67%, p=0.28) or median OS (low: 38.1 months, intermediate: 25.8 months, high: NR, p=0.15). Patients with weight loss >5% did not experience more grade 3-4 toxicity (92% vs. 87%, p=0.73), had similar median PFS (24.0 vs. 15.9 months, p=0.69), 2-year survival (64.0% vs. 66.2%, p=0.84) and median OS (30.6 vs. 35.1 months, p=0.93) as those without. Conclusions: Our study suggest that LS SCLC patients tolerate and should receive concurrent chemotherapy and twice-daily TRT regardless of nutritional status and weight loss.