The role of thoracic radiation therapy in the management of limited-stage small cell lung cancer (SCLC) is reviewed. Although chest irradiation has been used to treat SCLC for over four decades, its standard role in the management of limited-stage disease was established only during the last decade. Multiple prospective randomized trials have shown that the addition of thoracic radiation therapy to chemotherapy usually halves local failure rates, from >60% with chemotherapy alone to about 30% with chemoradiation therapy. Additionally, survival at 3 years is also improved by 50%, from 10% with chemotherapy alone to about 15% with chemoradiation therapy. However, issues relating to the timing, volume (ie, prechemotherapy vs postchemotherapy), and the dose fractionation scheme of thoracic radiation therapy in the treatment of limited-stage SCLC still remain unresolved. Recent review of the literature indicates the most optimal timing of thoracic radiation therapy appears to be concurrent with chemotherapy vs either a sequential or an alternating approach. Studies are currently under way evaluating the optimal volume and dose fractionation scheme to use in the delivery of thoracic radiation therapy. In summary, thoracic radiation therapy significantly improves both local chest control and survival in the treatment of limited-stage SCLC.