Small-cell lung cancer (SCLC) presenting with syncope as the initial symptom is rare in adults. This onset of tumour-induced syncope cannot be screened or differentiated by coronary angiography, magnetic resonance angiography of the neck or 24-hour dynamic electrocardiogram. We herein describe the case of a 61-year-old man who presented with recurrent syncope that resolved after the first course of chemotherapy (carboplatin plus etoposide) for SCLC. A mass measuring 57×53 mm was identified in the left hilum, and a diagnosis of limited-disease SCLC (T4N2M0, IIIB) was made. Considering the rapid and complete remission after the treatment of the primary lesion, we hypothesised that the syncope was neurogenic and associated with cancer. Thus, 8 similar cases retrieved from PubMed were reviewed and, for the first time, the mechanism underlying the syncope was identified, which may involve tumour location, neurobiology and other inducing factors. Thus, for the treatment of such SCLC patients, standard chemotherapy is crucial for preventing syncopal attacks.