Abstract: Objective To implement simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) plans for curingneck and upper thoracic esophageal carcinoma, and investigate the acute toxicity and early response. Methods SIB-IMRT plans were designed for 27 patients with neck and upper thoracic carcinoma. Two target volumes were predefined: PTV1, the target volume of primary lesion, which was given66Gy(2.2×30 fractions); PTV2, the target volumes of electively treated lesion, which was given54Gy(1.8×30 fractions).The plans were with coplanar beams. Results All the patients completed the treatment within 6 weeks. Only one with grade 3 acute bronchitis was observed. The immediate responses were CR 85.2% (23/27), PR 14.8%(4/27), overall response was 100% in esophageal lesion and CR 70.6% (12/17), PR 29.4%(5/17) in lymph node lesion. Conclusion Five coplanar beams IMRT can produce desirable dose distribution for SIB treatment of neck and upper thoracic esophageal carcinoma, especially the one with positive lymph node. Immediate response is satisfying and acute toxicity is not severe. But long-term effect and late toxicity need to be further studied.