Sequential chemotherapy and individualised accelerated radiotherapy (INDAR) has been shown to be effective in non-small cell lung cancer (NSCLC), allowing delivering of high biological doses. We therefore performed a phase II trial (clinicaltrials.gov; NCT00572325) investigating the same strategy in concurrent chemo-radiation in stage III NSCLC.137 stage III patients fit for concurrent chemo-radiation (PS 0-2; FEV 1 and DLCO ⩾30%) were included from April 2006 till December 2009. An individualised prescribed dose based on normal tissue dose constraints was applied: mean lung dose (MLD) 19Gy, spinal cord 54Gy, brachial plexus 66Gy, central structures 74Gy. A total dose between 51 and 69Gy was delivered in 1.5Gy BID up to 45Gy, followed by 2Gy QD. Radiotherapy was started at the 2nd or 3rd course of chemotherapy. Primary end-point was overall survival (OS) and secondary end-point toxicity common terminology criteria for adverse events v3.0 (CTCAEv3.0).The median tumour volume was 76.4±94.1cc; 49.6% of patients had N2 and 32.1% N3 disease. The median dose was 65.0±6.0Gy delivered in 35±5.7days. Six patients (4.4%) did not complete radiotherapy. With a median follow-up of 30.9months, the median OS was 25.0months (2-year OS 52.4%). Severe acute toxicity (⩾G3, 35.8%) consisted mainly of G3 dysphagia during radiotherapy (25.5%). Severe late toxicity (⩾G3) was observed in 10 patients (7.3%).INDAR in concurrent chemo-radiation based on normal tissue constraints is feasible, even in patients with large tumour volumes and multi-level N2–3 disease, with acceptable severe late toxicity and promising 2-year survival.