OBJECTIVE: Uncertainty exists regarding the optimal surveillance imaging schedule following definitive chemoradiation (CRT) for locally advanced non-small-cell lung cancer (LA-NSCLC) with regards to both frequency and modality. We sought to document the clinical impact of frequent (at least every 4 months) surveillance imaging. MATERIALS AND METHODS: The records of all patients treated with CRT for stage IIIA/IIIB NSCLC between August 1999 and April 2014 were reviewed. Patients were included if they underwent frequent (at least every 4 months) chest computed tomography or positron emission tomography for routine surveillance following CRT for at least 1 year or until progression or death. Radiographic findings and clinical interventions within the first year were identified. RESULTS: We identified 145 patients with LA-NSCLC treated with CRT, 63 with eligible imaging. Median age was 63.6 years (range, 41.0-86.9 years). Asymptomatic recurrence was radiographically detected in 38 (60.3%). Twenty-one (33.3%) initiated systemic therapy. Two (3.2%) underwent definitive-intent treatment for isolated disease, including lobectomy for a histologically distinct primary NSCLC and stereotactic radiotherapy for an isolated recurrence, both of whom subsequently progressed. Eleven patients (17.5%) received no further therapy. Five patients (7.9%) underwent additional diagnostic procedures for false-positive findings. CONCLUSIONS: Frequent surveillance within the first year following CRT for LA-NSCLC lung cancer detects asymptomatic recurrence in a high proportion of patients. However, definitive-intent interventions were infrequent. The predominant benefit of frequent surveillance appears to be expedient initiation of palliative systemic therapy. Evidence-based algorithms for surveillance are needed, and should account for expected patient tolerance of and willingness to undergo additional cancer-directed therapies.